feat(deployment): add secure Linux runtime (#17)

.dockerignore

@@ -0,0 +1,13 @@
+.git
+.gitea
+.idea
+.vs
+.codex
+.agents
+**/bin
+**/obj
+TestResults
+deploy/compose/secrets
+deploy/compose/.smoke.env
+docs
+tests

.gitea/workflows/ci.yml

@@ -35,3 +35,113 @@ jobs:
 
       - name: Test
         run: dotnet test Rendezvous.slnx --configuration Release --no-build
+
+      - name: Test privileged Linux namespace topology when available
+        shell: bash
+        run: |
+          set -euo pipefail
+          probe="rendezvous-probe-$$"
+          suffix="$(( $$ % 100000 ))"
+          bridge="rvb${suffix}"
+          veth_root="rvr${suffix}"
+          veth_peer="rvp${suffix}"
+          cleanup_probe() {
+            if [[ -n "$veth_root" ]]; then
+              ip link delete "$veth_root" >/dev/null 2>&1 || true
+            fi
+            if [[ -n "$bridge" ]]; then
+              ip link delete "$bridge" >/dev/null 2>&1 || true
+            fi
+            if [[ -n "$probe" ]]; then
+              ip netns delete "$probe" >/dev/null 2>&1 || true
+            fi
+          }
+          trap cleanup_probe EXIT
+          if command -v ip >/dev/null 2>&1 \
+            && command -v iptables >/dev/null 2>&1 \
+            && command -v sysctl >/dev/null 2>&1 \
+            && ip netns add "$probe" 2>/dev/null \
+            && ip link add "$bridge" type bridge \
+            && ip link add "$veth_root" type veth peer name "$veth_peer" \
+            && ip link set "$veth_root" master "$bridge" \
+            && ip link set "$veth_peer" netns "$probe" \
+            && ip netns exec "$probe" sysctl -q -w net.ipv4.ip_forward=1 \
+            && ip netns exec "$probe" iptables -t nat -A POSTROUTING -o "$veth_peer" -j MASQUERADE \
+            && ip netns exec "$probe" iptables -A FORWARD -i "$veth_peer" -o lo \
+              -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT; then
+            ip link delete "$veth_root"
+            veth_root=""
+            ip link delete "$bridge"
+            bridge=""
+            ip netns delete "$probe"
+            probe=""
+            results="${RUNNER_TEMP:-/tmp}/rendezvous-netns-results"
+            mkdir -p "$results"
+            RENDEZVOUS_RUN_NETNS_TESTS=1 dotnet test Rendezvous.slnx \
+              --configuration Release \
+              --no-build \
+              --filter FullyQualifiedName~PrivilegedLinuxNatNamespacesCompleteDirectTrafficAcrossSeparateObservedEndpoints \
+              --logger "trx;LogFileName=netns.trx" \
+              --results-directory "$results"
+            grep -q 'testName="[^"]*\.PrivilegedLinuxNatNamespacesCompleteDirectTrafficAcrossSeparateObservedEndpoints"' \
+              "$results/netns.trx"
+          else
+            echo "Network namespaces/NAT tooling unavailable; deterministic loopback topology remains the required gate."
+          fi
+
+  container:
+    needs: quality
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Install .NET SDK
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 10.0.301
+
+      - name: Build deployment diagnostic
+        run: |
+          dotnet restore src/FinalFactory.Rendezvous.TestClient/FinalFactory.Rendezvous.TestClient.csproj --locked-mode
+          dotnet build src/FinalFactory.Rendezvous.TestClient/FinalFactory.Rendezvous.TestClient.csproj --configuration Release --no-restore
+
+      - name: Build and exercise hardened container
+        shell: bash
+        run: |
+          set -euo pipefail
+          compose_file="deploy/compose/compose.yaml"
+          secret="deploy/compose/secrets/signing-key"
+          cleanup() {
+            RENDEZVOUS_UID=1654 RENDEZVOUS_GID=1654 \
+              docker compose -f "$compose_file" down --volumes >/dev/null 2>&1 || true
+            rm -f "$secret"
+          }
+          trap cleanup EXIT
+          install -d -m 0700 deploy/compose/secrets
+          openssl rand -out "$secret" 32
+          chmod 0444 "$secret"
+          export RENDEZVOUS_UID=1654
+          export RENDEZVOUS_GID=1654
+          docker compose -f "$compose_file" up --build --detach
+          container_id="$(docker compose -f "$compose_file" ps -q rendezvous)"
+          test -n "$container_id"
+          test "$(docker inspect --format '{{.Config.User}}' "$container_id")" = "1654:1654"
+          test "$(docker inspect --format '{{.HostConfig.ReadonlyRootfs}}' "$container_id")" = "true"
+          test "$(docker inspect --format '{{range .Mounts}}{{if eq .Destination \"/app/appsettings.Production.json\"}}{{.RW}}{{end}}{{end}}' "$container_id")" = "false"
+          test "$(docker inspect --format '{{range .Mounts}}{{if eq .Destination \"/run/secrets/rendezvous-signing-key\"}}{{.RW}}{{end}}{{end}}' "$container_id")" = "false"
+          for attempt in {1..100}; do
+            if curl --fail --silent http://127.0.0.1:8080/health/ready >/dev/null 2>&1; then
+              break
+            fi
+            if (( attempt == 100 )); then
+              docker compose -f "$compose_file" logs rendezvous
+              exit 1
+            fi
+            sleep 0.1
+          done
+          ./scripts/smoke-deployment.sh
+          docker compose -f "$compose_file" stop --timeout 40 rendezvous
+          test "$(docker inspect --format '{{.State.Running}}' "$container_id")" = "false"
+          test "$(docker inspect --format '{{.State.ExitCode}}' "$container_id")" = "0"

.gitignore

@@ -6,3 +6,6 @@ TestResults/
 *.suo
 *.user
 *.userosscache
+deploy/compose/.smoke.env
+deploy/compose/secrets/*
+!deploy/compose/secrets/.gitignore

Dockerfile

@@ -0,0 +1,30 @@
+# syntax=docker/dockerfile:1.7@sha256:a57df69d0ea827fb7266491f2813635de6f17269be881f696fbfdf2d83dda33e
+FROM mcr.microsoft.com/dotnet/sdk:10.0.301-noble@sha256:ea8bde36c11b6e7eec2656d0e59101d4462f6bd630730f2c8201ed0572b295d5 AS build
+
+WORKDIR /source
+COPY Directory.Build.props Directory.Packages.props NuGet.config global.json Rendezvous.slnx ./
+COPY src/FinalFactory.Rendezvous.Contracts/FinalFactory.Rendezvous.Contracts.csproj src/FinalFactory.Rendezvous.Contracts/packages.lock.json src/FinalFactory.Rendezvous.Contracts/
+COPY src/FinalFactory.Rendezvous.Server/FinalFactory.Rendezvous.Server.csproj src/FinalFactory.Rendezvous.Server/packages.lock.json src/FinalFactory.Rendezvous.Server/
+RUN dotnet restore src/FinalFactory.Rendezvous.Server/FinalFactory.Rendezvous.Server.csproj --locked-mode
+
+COPY src/FinalFactory.Rendezvous.Contracts/ src/FinalFactory.Rendezvous.Contracts/
+COPY src/FinalFactory.Rendezvous.Server/ src/FinalFactory.Rendezvous.Server/
+RUN dotnet publish src/FinalFactory.Rendezvous.Server/FinalFactory.Rendezvous.Server.csproj \
+    --configuration Release \
+    --no-restore \
+    --output /out \
+    /p:UseAppHost=false \
+    /p:OpenApiGenerateDocuments=false
+
+FROM mcr.microsoft.com/dotnet/aspnet:10.0.9-noble-chiseled@sha256:f820c4fbfb8bb204c3bbe05c69d48cd039cd0e67aa8f13ac1cec168819b90643 AS runtime
+
+ENV ASPNETCORE_HTTP_PORTS=8080 \
+    DOTNET_EnableDiagnostics=0 \
+    DOTNET_CLI_TELEMETRY_OPTOUT=1 \
+    TMPDIR=/tmp
+WORKDIR /app
+COPY --from=build --chown=1654:1654 /out/ ./
+USER 1654:1654
+EXPOSE 8080/tcp
+EXPOSE 9050/udp
+ENTRYPOINT ["dotnet", "FinalFactory.Rendezvous.Server.dll"]

README.md

@@ -38,7 +38,11 @@ UDP hole punching cannot guarantee a direct connection through every network. Sy
 - `FinalFactory.Rendezvous.TestClient` — thin interactive and scriptable host/browser/join diagnostic built only on the public SDK.
 - `FinalFactory.Rendezvous.Tests` — unit, integration, security, and connection-lifecycle tests.
 
-The server directory and NAT mediator begin as separate modules in one deployable service because they share session, lease, authorization, and endpoint state. Their internal boundary should allow independent deployment later if scale, availability, or security requirements diverge.
+The server directory and NAT mediator are separate modules in one single-active
+deployable service because they share ephemeral session, lease, authorization,
+replay, and endpoint state. Their internal boundary can support a future
+explicitly designed shared-state architecture; operators must not create
+multiple active v1 replicas.
 
 ## Service boundaries
 
@@ -77,9 +81,11 @@ The initial service does not provide:
 
 Rendezvous is under active roadmap development. The versioned contracts,
 directory leases, authenticated join attempts, LiteNetLib mediator, caller-owned
-SDK coordination, typed connection outcomes, and thin public-SDK diagnostic client
-are implemented. Deployment hardening, the broader NAT-topology harness, and
-the production-readiness roadmap remain in progress;
+SDK coordination, typed connection outcomes, thin public-SDK diagnostic client,
+deterministic NAT topology harness, hostile-input controls,
+observability/operator surface, and secure single-active Linux deployment are
+implemented. Capacity, resilience, packaging, and final production-readiness
+gates remain in progress;
 participating games must not treat the current repository as a finished production
 service until those gates land.
 
@@ -89,8 +95,19 @@ The frozen v1 wire surface is documented in the
 [HTTP, UDP, and generated OpenAPI contracts](docs/contracts/README.md).
 Tenant policy, publisher/operator principals, and production key custody are
 defined in [game provisioning and signing-key lifecycle](docs/security/provisioning.md).
+Layered HTTP/UDP budgets, overload behavior, and safe operational tuning are
+defined in [hostile-input and overload protection](docs/security/abuse-protection.md).
+Health semantics, bounded telemetry, alerting, audit privacy, and the authenticated
+operator controls are defined in the
+[observability and operator runbook](docs/operations/observability-and-operator-runbook.md).
+The pinned non-root container, production topology, graceful drain, Linux
+hardening, smoke procedure, and recovery lifecycle are documented in
+[secure single-active Linux deployment](docs/deployment/linux.md).
 The scriptable host/browser/join diagnostic and its stable automation contract are
 documented in the [TestClient integration guide](docs/integration/test-client.md).
+The always-on three-party scenarios, optional Linux namespace topology, and
+simulation limits are documented in the
+[deterministic topology harness](docs/integration/topology-harness.md).
 
 ## Development
 
@@ -107,9 +124,11 @@ dotnet test Rendezvous.slnx --configuration Release --no-build
 Run the bootstrap server with
 `dotnet run --project src/FinalFactory.Rendezvous.Server`. It serves HTTP health endpoints and binds
 the configured UDP mediator port; both stop through normal host cancellation.
-The launch profile uses an ephemeral development-only signing key. Production
-startup fails closed until externally supplied game policies and `env:` signing
-key references resolve to valid key material; no reusable game secret is stored
+The launch profile uses separate ephemeral development-only publisher and operator
+signing keys. Production
+startup fails closed until its advertised endpoints, proxy trust boundary,
+externally supplied game policies, and `env:` (base64) or `file:` (raw,
+absolute, non-symlink) signing-key references resolve safely; no reusable game secret is stored
 in this repository or the public Client package.
 The project dependency rules and supported runtime choices are documented in
 [project and dependency boundaries](docs/architecture/project-boundaries.md).

deploy/compose/appsettings.Production.json

@@ -0,0 +1,58 @@
+{
+  "AllowedHosts": "localhost;127.0.0.1",
+  "Rendezvous": {
+    "Deployment": {
+      "PublicHttpBaseUrl": "https://localhost/",
+      "PublicUdpHost": "127.0.0.1",
+      "PublicUdpPort": 9050,
+      "DrainDeadlineSeconds": 30,
+      "MinimumDrainSeconds": 1,
+      "SingleActiveInstance": true,
+      "AllowPrivatePublicEndpoints": true
+    },
+    "Udp": {
+      "ListenAddress": "0.0.0.0",
+      "Port": 9050
+    },
+    "AbuseProtection": {
+      "TrustedProxyAddresses": ["127.0.0.1"],
+      "OperatorAllowedAddresses": ["127.0.0.1"]
+    },
+    "Provisioning": {
+      "Issuer": "final-factory-rendezvous-smoke",
+      "Audience": "rendezvous-service",
+      "ClockSkewSeconds": 30,
+      "SigningKeys": [
+        {
+          "KeyId": "local-smoke-1",
+          "SecretReference": "file:/run/secrets/rendezvous-signing-key",
+          "CredentialKinds": ["DedicatedPublisher"],
+          "GameId": "space-game",
+          "EnvironmentId": "smoke",
+          "NotBefore": "2026-01-01T00:00:00Z",
+          "SignUntil": "2100-01-01T00:00:00Z",
+          "VerifyUntil": "2100-01-02T00:00:00Z"
+        }
+      ],
+      "Games": [
+        {
+          "GameId": "space-game",
+          "EnvironmentId": "smoke",
+          "Enabled": true,
+          "ProtocolVersions": [1],
+          "Regions": ["local"],
+          "VisibilityModes": ["Public"],
+          "PublisherTrustModes": ["ManagedDedicated"],
+          "MetadataValueMaxBytes": {},
+          "RequiredMetadataKeys": [],
+          "MetadataMaxBytes": 512,
+          "MetadataMaxKeys": 0,
+          "MaxListingsPerPrincipal": 10,
+          "MaxAnonymousListingsPerAddress": 0,
+          "MaxActiveJoinAttempts": 100,
+          "FallbackPolicy": "Disabled"
+        }
+      ]
+    }
+  }
+}

deploy/compose/compose.yaml

@@ -0,0 +1,35 @@
+name: rendezvous-local
+
+services:
+  rendezvous:
+    image: finalfactory/rendezvous:local
+    build:
+      context: ../..
+      dockerfile: Dockerfile
+    init: true
+    user: "${RENDEZVOUS_UID:?set RENDEZVOUS_UID to a non-root host UID}:${RENDEZVOUS_GID:?set RENDEZVOUS_GID to its GID}"
+    read_only: true
+    tmpfs:
+      - /tmp:rw,noexec,nosuid,nodev,size=16m,uid=${RENDEZVOUS_UID},gid=${RENDEZVOUS_GID},mode=0700
+    cap_drop:
+      - ALL
+    security_opt:
+      - no-new-privileges:true
+    pids_limit: 128
+    mem_limit: 512m
+    cpus: 1.0
+    ulimits:
+      nofile:
+        soft: 4096
+        hard: 4096
+    stop_grace_period: 40s
+    restart: unless-stopped
+    environment:
+      ASPNETCORE_ENVIRONMENT: Production
+      ASPNETCORE_HTTP_PORTS: "8080"
+    volumes:
+      - ./appsettings.Production.json:/app/appsettings.Production.json:ro
+      - ./secrets/signing-key:/run/secrets/rendezvous-signing-key:ro
+    ports:
+      - "127.0.0.1:8080:8080/tcp"
+      - "9050:9050/udp"

deploy/compose/secrets/.gitignore

@@ -0,0 +1,2 @@
+*
+!.gitignore

deploy/systemd/rendezvous.service

@@ -0,0 +1,47 @@
+[Unit]
+Description=Final Factory Rendezvous service
+Documentation=https://git.finalfactory.de/HeiKyu/Rendezvous
+After=network-online.target time-sync.target
+Wants=network-online.target time-sync.target
+
+[Service]
+Type=simple
+User=rendezvous
+Group=rendezvous
+WorkingDirectory=/opt/rendezvous
+ExecStart=/usr/bin/dotnet /opt/rendezvous/FinalFactory.Rendezvous.Server.dll
+Environment=ASPNETCORE_ENVIRONMENT=Production
+Environment=ASPNETCORE_HTTP_PORTS=8080
+Environment=DOTNET_EnableDiagnostics=0
+EnvironmentFile=-/etc/rendezvous/rendezvous.env
+Restart=on-failure
+RestartSec=5s
+KillSignal=SIGTERM
+KillMode=mixed
+TimeoutStopSec=40s
+NoNewPrivileges=true
+PrivateDevices=true
+PrivateTmp=true
+ProtectClock=true
+ProtectControlGroups=true
+ProtectHome=true
+ProtectHostname=true
+ProtectKernelLogs=true
+ProtectKernelModules=true
+ProtectKernelTunables=true
+ProtectSystem=strict
+RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6
+RestrictNamespaces=true
+RestrictRealtime=true
+RestrictSUIDSGID=true
+CapabilityBoundingSet=
+AmbientCapabilities=
+LockPersonality=true
+SystemCallArchitectures=native
+UMask=0077
+LimitNOFILE=4096
+MemoryMax=512M
+TasksMax=128
+
+[Install]
+WantedBy=multi-user.target

docs/deployment/linux.md

@@ -0,0 +1,225 @@
+# Secure single-active Linux deployment
+
+Tracking: #17
+
+Rendezvous v1 stores listings, observed endpoints, join attempts, replay markers,
+and runtime revocations only in the process that accepted them. Deploy exactly
+one active instance. A second live replica would have a different directory and
+replay boundary; `SingleActiveInstance=false` is therefore rejected rather than
+presented as high availability.
+
+## Pinned container
+
+The root `Dockerfile` uses a multi-stage .NET 10 build and pins both Microsoft
+base images by multi-architecture manifest digest. The runtime is the chiseled
+ASP.NET image, contains only the published server, runs as UID/GID 1654, exposes
+TCP 8080 and UDP 9050 explicitly, and does not require a writable application
+directory. Supply a small writable `/tmp` tmpfs because runtime libraries can
+legitimately need temporary space; keep the root filesystem read-only.
+
+From a clean checkout:
+
+```bash
+docker build --pull=false --tag finalfactory/rendezvous:local .
+docker inspect --format '{{.Config.User}}' finalfactory/rendezvous:local
+```
+
+The reported user must be `1654:1654`. Digest pins make a rebuild reproducible;
+updating .NET is an explicit reviewed change to the tag, digest, SDK pin, and
+lock files together. Do not replace the digest with `latest` in production.
+
+The local Compose example applies a read-only root, non-root user, no Linux
+capabilities, `no-new-privileges`, bounded PIDs/files/memory/CPU, and a shutdown
+grace period longer than the service drain deadline:
+
+```bash
+install -d -m 0700 deploy/compose/secrets
+umask 077
+openssl rand -out deploy/compose/secrets/signing-key 32
+export RENDEZVOUS_UID="$(id -u)"
+export RENDEZVOUS_GID="$(id -g)"
+test "$RENDEZVOUS_UID" -ne 0
+docker compose -f deploy/compose/compose.yaml up --build --detach
+```
+
+`deploy/compose/appsettings.Production.json` is an isolated loopback smoke
+profile, not an Internet template: it deliberately opts into private advertised
+endpoints and has no TLS proxy. Its random key is ignored by Git and must be
+deleted after use. Its deliberately long key window only keeps this disposable
+local fixture usable; production keys require short, reviewed rotation windows.
+Production configuration must use its real public names and must leave
+`AllowPrivatePublicEndpoints` false.
+
+## Production topology
+
+Use one active service behind a source-preserving edge:
+
+```text
+clients -- HTTPS/443 --> TLS reverse proxy -- HTTP/8080 --> Rendezvous
+clients -- UDP/9050 -------------------------------------> Rendezvous
+```
+
+- Give the HTTPS origin and UDP endpoint stable DNS names. Set
+  `PublicHttpBaseUrl` to the exact external HTTPS origin and `PublicUdpHost` /
+  `PublicUdpPort` to the endpoint given to game clients.
+- Terminate TLS 1.2 or newer at a maintained reverse proxy. Bind internal HTTP
+  only to the private proxy network. Restrict `AllowedHosts` to the public HTTP
+  host; wildcard host filtering is rejected.
+- Put only the proxy's exact literal addresses in
+  `Rendezvous:AbuseProtection:TrustedProxyAddresses`. Rendezvous ignores
+  forwarded headers from every other source. Keep the last proxy from replacing
+  the original client address and prevent direct access to TCP 8080.
+- Forward UDP as UDP, without an HTTP proxy. NAT, load balancer, firewall, and
+  return routing must preserve the client's source IP/port and must send replies
+  from the same advertised IP/port. Many HTTP load balancers, Kubernetes ingress
+  controllers, rootless container port proxies, anycast products, and generic
+  L7 services cannot guarantee this. Do not deploy through one unless an actual
+  host/join smoke proves both observed source and reply path. A load balancer
+  must have exactly one healthy Rendezvous target.
+- Permit inbound TCP 443 to the TLS proxy and UDP 9050 to Rendezvous. Permit the
+  proxy to reach TCP 8080. Permit DNS, time synchronization, image/telemetry
+  destinations as required by local policy, and UDP replies to client endpoints.
+  Deny public TCP 8080 and every unused inbound port.
+
+Readiness is the load-balancer gate; liveness is only a process-health signal.
+Remove a draining instance from new traffic when `/health/ready` becomes 503.
+Do not use liveness failure to start a second active process while the old one
+still owns the public UDP address.
+
+## Required production configuration
+
+Production startup validates all of these before binding listeners:
+
+- an absolute path-free HTTPS `PublicHttpBaseUrl`;
+- an unambiguous public `PublicUdpHost` and port;
+- `SingleActiveInstance=true`, an explicit non-wildcard `AllowedHosts`, and at
+  least one exact trusted TLS-proxy address;
+- a 1-30 second drain deadline whose minimum observation interval is shorter;
+- at least one enabled game policy and an active scoped signing key.
+
+Missing values produce an actionable startup error. The checked-in base file is
+intentionally unsafe for Production so an accidental bare launch fails closed.
+
+Signing keys support two external references:
+
+- `env:NAME` reads 1-4096 bytes encoded as base64 from `NAME`;
+- `file:/absolute/path` reads 1-4096 raw bytes from a non-symlink file.
+
+Prefer a read-only container secret owned by the configured container identity.
+For systemd, use a root-owned, `rendezvous`-group-owned `0440` file (or an
+equivalent narrow ACL) so the non-root process can read but not replace it. A
+signing key must contain at least 32 random bytes. Never put the key, publisher/operator
+credential, or secret value in JSON, a command argument, an image layer, Compose
+environment, logs, metrics, or source control. Configuration contains only the
+reference and non-secret lifecycle metadata. A vault/KMS adapter can replace the
+provider where local policy requires it.
+
+Keep the host clock synchronized with authenticated NTP. Credential and key
+windows use wall time; lease, timeout, drain, and rate-limit deadlines use a
+monotonic clock. Alert on clock synchronization loss before rotating keys.
+
+Start with the Compose limits (one CPU, 512 MiB, 128 PIDs, 4096 descriptors),
+measure real traffic, then change the limits and the server budgets together.
+Memory pressure or CPU throttling must not extend orchestrator termination past
+`DrainDeadlineSeconds` plus five seconds.
+
+## Graceful shutdown
+
+SIGTERM and the authenticated operator drain both stop new registrations and
+join attempts immediately. On process shutdown, HTTP and UDP remain available
+long enough for existing join attempts to finish. The service exits as soon as
+the minimum drain interval has elapsed and no attempts remain, or forcibly
+clears all ephemeral state at the configured deadline. It then stops UDP and
+HTTP listeners and exits. Configure Docker/systemd/Kubernetes termination grace
+strictly longer than the service deadline; the examples use 40 seconds for a
+30-second drain.
+
+Never use SIGKILL for a normal rollout. After stopping, verify the process is
+gone and neither `8080/tcp` nor `9050/udp` is bound before starting its
+replacement on the same host. A crashed or force-killed process cannot drain;
+clients recover through bounded retries and hosts re-register.
+
+## systemd alternative
+
+Publish the server for Linux, install the immutable output at `/opt/rendezvous`,
+place production configuration beside the application read-only, place key
+files below `/etc/rendezvous`, and install `deploy/systemd/rendezvous.service`:
+
+```bash
+dotnet publish src/FinalFactory.Rendezvous.Server \
+  --configuration Release --runtime linux-x64 --self-contained false \
+  --output publish/rendezvous
+systemd-analyze verify deploy/systemd/rendezvous.service
+sudo systemctl daemon-reload
+sudo systemctl enable --now rendezvous.service
+```
+
+Create the dedicated `rendezvous` user without a login shell. Keep
+`/opt/rendezvous` and `/etc/rendezvous` root-owned and non-writable by that user;
+install each required key with `root:rendezvous` ownership and mode `0440`. The
+unit applies the same resource, filesystem, privilege, network-family, and
+shutdown constraints as Compose.
+
+## HTTP and UDP smoke
+
+Build the diagnostic once, then exercise the actual published HTTP and UDP
+paths. The test creates a public listing, sends authenticated presence and punch
+traffic through UDP 9050, establishes peer-to-peer traffic, reports the outcome,
+and deregisters cleanly:
+
+```bash
+dotnet build src/FinalFactory.Rendezvous.TestClient --configuration Release
+./scripts/smoke-deployment.sh
+```
+
+For the local Compose profile, the script derives a ten-minute diagnostic
+publisher credential from the ignored local key without printing either secret.
+For production, do not copy the signing key to the smoke host. Instead inject a
+short-lived, region-scoped credential through
+`RENDEZVOUS_PUBLISHER_CREDENTIAL`, and set the external endpoints:
+
+```bash
+export RENDEZVOUS_PUBLISHER_CREDENTIAL='<short-lived deployment credential>'
+export RENDEZVOUS_SMOKE_HTTP_URL='https://rendezvous.your-company.tld/'
+export RENDEZVOUS_SMOKE_UDP_ENDPOINT='rendezvous-udp.your-company.tld:9050'
+export RENDEZVOUS_SMOKE_GAME_ID='<credential game ID>'
+export RENDEZVOUS_SMOKE_ENVIRONMENT_ID='<credential environment ID>'
+export RENDEZVOUS_SMOKE_REGION='<credential region>'
+export RENDEZVOUS_SMOKE_PROTOCOL_VERSION='<enabled protocol version>'
+./scripts/smoke-deployment.sh
+```
+
+Those four scope values must match both the short-lived credential and an
+enabled server policy. The defaults (`space-game`, `smoke`, `local`, protocol
+`1`) are only for the checked-in local Compose profile.
+
+The smoke fails unless both health endpoints and the complete authenticated UDP
+mediation/direct-traffic flow succeed. It does not prove every consumer NAT;
+run the topology harness and representative external-network tests as well.
+
+## Restart, upgrade, rollback, and backup
+
+Rendezvous has no durable runtime database. Restarting intentionally loses all
+listings, observed endpoints, attempts, replay markers, and runtime-only
+revocations. Hosts must treat registration as a renewable lease and re-register
+after service recovery. Clients must re-browse and start a new bounded attempt.
+
+Back up only reviewed configuration, policy, secret references, key material and
+its custody/lifecycle records, deployment manifests, and image digest. Never
+claim a backup contains live sessions or endpoints. Restore keys only through the
+secret system, not into the image or repository.
+
+For an upgrade:
+
+1. Build and test the new pinned digest; validate configuration without starting
+   a second active instance.
+2. Drain and stop the current process, verify both sockets are released, then
+   start the replacement on the same public endpoints.
+3. Require live/readiness and HTTP+UDP smoke success; monitor host
+   re-registration, error rate, and direct-connect outcomes.
+
+For rollback, repeat the same stop-before-start sequence with the previously
+recorded image digest and compatible configuration/key set. Never run old and
+new versions concurrently to avoid split ephemeral state. If a wire-incompatible
+change ever becomes necessary, use a new API/protocol version rather than a
+rolling two-version replica set.

docs/integration/test-client.md

@@ -7,6 +7,9 @@ It exists for integration development, CI smoke checks, deployment verification,
 and operator diagnosis. It is intentionally not a production game client, game
 server, matchmaking UI, or relay.
 
+The automated scenario matrix, privileged Linux namespace run, and topology
+limitations are documented in the [deterministic topology harness](topology-harness.md).
+
 ## Prerequisites
 
 Start a configured Rendezvous service and note both its HTTP base URL and UDP

docs/integration/topology-harness.md

@@ -0,0 +1,91 @@
+# Deterministic topology harness
+
+Issue #14 is verified at three layers. The layers are deliberately separate so
+the always-on gate remains deterministic while privileged CI workers can add a
+stronger operating-system topology without overstating what local emulation
+proves about the public Internet.
+
+## Always-on public-process gate
+
+`TestClientProcessIntegrationTests` launches the built server and the same
+`FinalFactory.Rendezvous.TestClient` executable shipped to operators. Every
+child process uses `--script --json`, dynamic HTTP and UDP ports, bounded
+state-driven waits, and enforced process-tree cleanup.
+
+The suite proves:
+
+| Scenario | Required observation |
+| --- | --- |
+| Three-party happy path | register, presence-ready, browse, authorize, punch, authenticated LiteNetLib connection, direct ping/echo/ack/completion traffic, outcome report, disconnect, deregister |
+| Same-LAN candidate | the connected peer is reported as `loopback` or `private`, never inferred merely from an introduction callback |
+| Empty and missing selection | browse exits `11`; exact missing lookup exits `10` |
+| Wrong tenant/protocol | no listing is returned for an incompatible protocol; exact joins with either mismatch fail before `join.punch` |
+| Traversal timeout | an unreachable mediator produces typed `PunchTimedOut`, exits `12`, advertises the configured dedicated fallback, and never connects to it |
+| Caller cancellation | POSIX `SIGINT` exits `130`, deregisters the listing, and removes it from public lookup |
+| Abrupt host loss | the listing disappears after the presence window and before its lease expires; public exact lookup intentionally reports `NotFound` |
+| Bounded host without a peer | exits `13` and still deregisters |
+
+Captured output is parsed as the stable JSON v1 event schema. Publisher
+credentials and signing-key material are checked against all captured output.
+The direct traffic payload is handled only by the caller-owned host and client
+LiteNetLib managers; the HTTP service and mediator do not implement or observe
+the echo protocol.
+
+Run the always-on scenarios with:
+
+```bash
+dotnet test Rendezvous.slnx --configuration Release --no-build \
+  --filter FullyQualifiedName~TestClientProcessIntegrationTests
+```
+
+## Deterministic protocol and adverse-state gate
+
+The following real service-boundary tests cover conditions that a public CLI
+cannot safely manufacture by accepting raw capabilities or tickets:
+
+| Scenario | Test evidence |
+| --- | --- |
+| Same-NAT private candidates | `NatMediationProcessorTests.MatchedPeersReceiveOneIntroductionAndSameNatPrivateCandidates` |
+| Separate observed endpoints | `NatMediationProcessorTests.DifferentNatsAndInvalidLocalClaimsExposeOnlyObservedPublicEndpoints` |
+| One-time introduction and replay | `InMemoryEphemeralRendezvousStoreTests.AttemptCapabilitiesAndIntroductionAreOneTime` |
+| Direct ticket replay | `RendezvousCoordinatorIntegrationTests.CallerOwnedManagersCompleteAuthenticatedDirectConnectionAndRejectTicketReplay` |
+| Wrong tenant/protocol and stale presence | `InMemoryEphemeralRendezvousStoreTests.JoinRequiresExactScopeProtocolAndFreshHostPresence` |
+| Cancellation and late callbacks | `RendezvousCoordinatorBehaviorTests.CancellationCompletesExactlyOnceAndLateCallbacksCannotReopenTheAttempt` |
+| Mediator restart | both cases of `UdpMediatorServiceTests.NativeLiteNetLibRequestsIntroduceTheAuthorizedPair`; the restarted case rebinds the same UDP port and completes a native LiteNetLib introduction |
+
+These tests use fake monotonic clocks or state predicates where expiry and race
+ordering matter. They do not use fixed sleeps as proof of state.
+
+## Privileged Linux namespace gate
+
+When a Linux CI worker can create network namespaces, the workflow sets
+`RENDEZVOUS_RUN_NETNS_TESTS=1` and reruns
+`PrivilegedLinuxNatNamespacesCompleteDirectTrafficAcrossSeparateObservedEndpoints`.
+The test creates a temporary WAN bridge, an isolated service namespace, two NAT
+router namespaces, and isolated host/client LAN namespaces. Each NAT has its own
+inside subnet and WAN address. Linux forwarding plus per-router MASQUERADE rules
+force the service to observe separate translated endpoints; the public TestClient
+processes must then complete authenticated direct traffic through those mappings
+using the public candidate. Namespaces, rules, veth pairs, bridge, processes, and
+sockets are removed in bounded async-disposal paths. A cleanup failure fails the
+test.
+
+If `ip netns add`/`iptables` is unavailable or the worker lacks `CAP_NET_ADMIN`,
+CI records the limitation and keeps the always-on loopback suite as the required gate.
+To request the privileged run explicitly:
+
+```bash
+RENDEZVOUS_RUN_NETNS_TESTS=1 dotnet test Rendezvous.slnx \
+  --configuration Release --no-build \
+  --filter FullyQualifiedName~PrivilegedLinuxNatNamespacesCompleteDirectTrafficAcrossSeparateObservedEndpoints
+```
+
+## What this does not prove
+
+Loopback, MASQUERADE, and namespace routing cannot reproduce every consumer router,
+carrier-grade NAT, firewall, IPv6 transition mechanism, symmetric NAT mapping,
+or real-world packet-loss pattern. The separate-observed-endpoint processor
+test proves that untrusted private claims are excluded and public candidates are
+selected; it is not presented as universal Internet traversal proof. Real
+network canaries and measured production readiness remain the scope of issue
+#23.

docs/operations/observability-and-operator-runbook.md

@@ -0,0 +1,142 @@
+# Observability and operator runbook
+
+This runbook defines the production signals and privileged controls for the
+Rendezvous service. The service emits `System.Diagnostics.Metrics` instruments
+from the `FinalFactory.Rendezvous` meter and distributed-tracing activities from
+`FinalFactory.Rendezvous.Server`. Connect those sources to the deployment's
+OpenTelemetry or equivalent collector. Do not add identifiers to metric labels.
+
+## Health and readiness
+
+- `GET /health/live` proves that the HTTP process can answer. It deliberately
+  remains independent of provisioning, the state store, drain state, and optional
+  listeners so an orchestrator does not restart a recoverable dependency failure.
+- `GET /health/ready` returns success only after the HTTP path is answering, the
+  required IPv4 UDP socket is bound, any configured IPv6 UDP socket is bound,
+  provisioning loaded successfully, the store is available, and drain has not
+  started. A failed check returns `503` and removes the instance from new work.
+- A graceful drain immediately makes readiness fail while liveness remains healthy.
+  Existing work may complete until the bounded store drain deadline.
+
+## Metrics and traces
+
+| Instrument | Purpose | Bounded dimensions |
+| --- | --- | --- |
+| `rendezvous.http.requests` / `rendezvous.http.duration` | HTTP volume and latency | operation, status code |
+| `rendezvous.udp.results` / `rendezvous.udp.duration` | UDP mediation volume and processing latency | frozen/litenet operation, result |
+| `rendezvous.limiter.drops` | Requests shed by admission controls | transport, fixed partition class |
+| `rendezvous.operator.authentication` | Accepted, forbidden, and rejected operator authentication | result |
+| `rendezvous.audit.events` | Privileged action outcomes | fixed action, result |
+| `rendezvous.connection.outcomes` | Client-reported direct-connect outcomes | normalized outcome, elapsed bucket |
+| `rendezvous.pairing.latency` | Time from attempt creation to successful peer introduction | none |
+| `rendezvous.queue.depth` | Active join-attempt queue depth | none |
+| `rendezvous.store.active_listings` / `active_leases` / `active_attempts` / `replay_markers` | Current ephemeral load | none |
+| `rendezvous.store.expiry_churn` | Cumulative natural expiry activity | none |
+| `rendezvous.store.available` | Store health (`1` available, `0` unavailable) | none |
+
+HTTP responses include `X-Rendezvous-Correlation-ID`. It is a generated trace ID
+or random value, never a caller-supplied session or player identifier. UDP and
+HTTP activities contain operation-level data only. Logs and traces must not add
+tokens, capabilities, session/listing IDs, player subjects, metadata, raw IP
+addresses, or endpoint values.
+
+Recommended dashboard panels are request rate and p50/p95/p99 latency by fixed
+operation, UDP result ratio, direct connection success ratio, pairing latency,
+active listings/attempts, expiry churn, limiter drops, store availability,
+operator authentication results, audit action results, and signing-key windows.
+
+## Alerts
+
+Tune thresholds from the normal production baseline, then keep these conditions
+as distinct actionable alerts:
+
+- **Signing key expiry:** page when any required signing key has less than seven
+  days before `signUntil`; escalate at 24 hours. Confirm a replacement is signing
+  and the previous key remains verify-only for the maximum credential lifetime.
+- **Authentication spike:** warn when rejected or forbidden operator authentication
+  exceeds five attempts in five minutes. Treat unexpected publisher-authentication
+  growth as a possible credential or integration incident.
+- **Direct success regression:** warn when the connected outcome ratio falls more
+  than 20% below its seven-day same-region baseline for 15 minutes, with a minimum
+  sample floor. Break down only by bounded outcome and time bucket.
+- **Saturation:** warn when queue depth remains above 70% of the configured attempt
+  limit, limiter drops are sustained, or p95 latency exceeds the service objective;
+  page at 90% or when lease-critical traffic is shed.
+- **Store degradation:** page immediately when `rendezvous.store.available` is zero
+  or readiness fails for the store. Rising expiry churn without corresponding new
+  work is a warning for stalled clients or clock/configuration mistakes.
+- **Listener/config readiness:** page when no ready instances remain. Investigate
+  UDP bind failures, a configured-but-unbound IPv6 listener, provisioning errors,
+  and unintended drain state separately.
+
+## Operator authentication and controls
+
+Operator credentials use a signing key configured with `CredentialKinds:
+["Operator"]`. Operator keys cannot be scoped to a game/environment or used for
+publisher credentials. Mint short-lived operator credentials through the trusted
+provisioning process, outside the public Rendezvous HTTP service, and grant only
+the required permission. Never place credentials in command history, URLs, logs,
+or support tickets.
+
+The application also enforces a default-deny source boundary. Configure at most
+32 exact operator source IPs in
+`Rendezvous:AbuseProtection:OperatorAllowedAddresses`; an empty list disables all
+operator HTTP access. Development permits loopback only. Production must place
+`/v1/operator/*` behind a private management listener or reverse-proxy ACL, list
+only the resulting trusted management source addresses, and block that path on
+the public edge. If forwarded headers are enabled, keep the existing exact-proxy,
+single-hop trust policy and allowlist the post-forwarding operator source. Verify
+from both an allowed management host and a denied public host before deployment.
+Denied sources are charged to the bounded general HTTP partition before credential
+or request-body processing, then receive `404`; sustained denied traffic receives
+the same typed `429` overload response as other public traffic.
+
+Operator traffic has a dedicated, bounded rate/concurrency partition and critical
+tracker-key reserve. Public browse/join saturation therefore cannot consume the
+operator control budget, while compromised management sources remain rate-limited.
+
+The OpenAPI document defines the separate `OperatorBearer` scheme. All endpoints
+are under `/v1/operator`:
+
+| Endpoint | Permission | Confirmation |
+| --- | --- | --- |
+| `GET /status` | `ReadPolicy` | none; returns aggregates, tenant status, safe key status, and audit counts |
+| `POST /listings/revoke` | `RevokePublisher` | repeat the exact listing ID in `confirmListingId` |
+| `POST /principals/revoke` | `RevokePublisher` | repeat the exact subject and choose a 1-600 second revocation lifetime |
+| `POST /keys/revoke` | `RotateKeys` | repeat the exact key ID; runtime revocation is immediate |
+| `POST /drain` | `ManagePolicy` | send the exact value `DRAIN` |
+
+Publisher credentials are rejected on this surface even if their subject resembles
+an operator. Destructive responses do not echo identifiers. The status response
+does not expose player identities, raw endpoints, session metadata, capabilities,
+or tokens. Every authenticated operator action, rejected confirmation, and
+permission denial is audited with actor and target fingerprints.
+
+Key revocation is process-local in the current single-instance store. Apply the
+same revocation to every instance, then replace configuration before restarting;
+a restart reconstructs the configured key ring. Principal revocation is bounded
+to ten minutes and removes that principal's active listings and attempts. Use
+listing revocation for one targeted session and drain before planned shutdown.
+
+## Audit retention and incident handling
+
+The in-process audit trail defaults to 10,000 entries and 30 days. It evicts the
+oldest record at capacity and purges expired records on the next write. Configure
+`Rendezvous:Audit:MaxEntries` and `RetentionDays` within their validated bounds.
+Export the structured `AuditTrail` log events through the deployment's protected
+logging pipeline when durable retention is required; the in-memory trail is not a
+durable compliance archive. Those events include only timestamps, fixed action
+fields, correlation IDs, and actor/target fingerprints.
+
+Audit records retain timestamp, fixed action/result, target kind, correlation ID,
+and 96-bit SHA-256 fingerprints of actor and target. Routine logs contain only the
+fixed action/result/target kind and correlation ID. Restrict audit access to the
+operator role, retain aggregates only as long as operationally necessary, and
+delete raw exported audit data according to the 30-day policy unless an incident
+hold is approved.
+
+During an incident: confirm readiness and store health; capture aggregate graphs
+and correlation IDs; revoke the narrowest listing, principal, or key; drain only
+when isolation is required; record the action in the incident timeline; and verify
+that direct success, limiter drops, and authentication rates return to baseline.
+Do not copy player data, endpoints, or credentials into the incident record.

docs/security/abuse-protection.md

@@ -0,0 +1,103 @@
+# Hostile-input and overload protection
+
+Tracking: #15
+
+Rendezvous treats every public HTTP request and UDP datagram as hostile. The
+server applies bounded fixed-window request budgets and concurrency ceilings in
+two stages so malformed input is discarded before expensive work while valid
+traffic is also isolated by its authenticated scope.
+
+## Enforcement order
+
+1. Kestrel and the HTTP abuse middleware cap request bodies at 16 KiB. A known
+   oversized body receives a typed `413` response before endpoint dispatch.
+2. Every HTTP request consumes global, source-prefix, and operation budgets and
+   acquires the corresponding concurrency leases. IPv4 sources share a `/24`
+   budget and IPv6 sources share a `/56` budget; raw addresses are not retained.
+   Non-lease operations also consume a smaller optional-work budget, leaving a
+   configured global and source-prefix reserve for renew, update, and delete
+   operations during shedding.
+   Health probes use their own source-prefix budget so public API overload cannot
+   make a healthy instance fail its orchestrator probes, while health traffic is
+   still bounded.
+   Operator endpoints likewise use a separate bounded rate/concurrency partition
+   backed by the critical tracker reserve. They first require an exact source IP
+   from the default-deny `OperatorAllowedAddresses` policy, so public traffic
+   cannot spend the incident-response budget.
+3. Once an endpoint has safely derived identities, it also acquires applicable
+   tenant, principal or capability, and listing/attempt budgets. Secret
+   capabilities are represented only by bounded SHA-256 fingerprints.
+4. Every UDP envelope consumes global, source-prefix, and wire-operation
+   budgets before decoding. A structurally and cryptographically valid request
+   then consumes capability, role, and mediation-handle budgets before state
+   mutation or introduction.
+5. HTTP overload returns the stable `RateLimited` error, status `429`, and a
+   bounded `Retry-After` value in both the header and response contract. UDP
+   overload and every invalid UDP input are silently dropped.
+
+The same HTTP identity budget is computed whether or not a listing or attempt
+exists. Rejection therefore does not disclose resource existence. Publisher
+authentication also completes before any tenant/resource operation, while the
+pre-authentication source budget prevents invalid credentials from bypassing
+load shedding.
+
+## Bounded state and recovery
+
+`Rendezvous:AbuseProtection:MaxTrackedKeys` is a hard combined ceiling for rate
+and active-concurrency keys. General HTTP and UDP traffic cannot consume the
+configured `CriticalTrackedKeyReserve`; lease operations, health probes, and
+allowlisted operator controls may
+use that reserve but never exceed the hard ceiling. A request that would exceed
+its applicable ceiling fails closed without adding state. Fixed-window rate keys
+are cleared at the next window boundary; concurrency keys are removed as their
+request leases finish. HTTP and UDP trackers have separate locks and cardinality
+partitions, so a UDP flood cannot block HTTP admission on a shared lock or
+consume HTTP key capacity. This gives
+deterministic burst recovery and prevents an attacker from growing a permanent
+high-cardinality address, credential, or resource table.
+
+The complete default profile is checked into
+`src/FinalFactory.Rendezvous.Server/appsettings.json`. Operators may lower or
+tune limits for a measured deployment profile, but must preserve all dimensions
+and leave the tracker ceiling above the maximum simultaneous key set. A rolling
+deployment should use the same profile on every instance. These per-process
+limits are a final service boundary; an edge proxy may add stricter distributed
+limits but is not a substitute for them.
+
+When an HTTP reverse proxy is used, every immediate proxy address must be
+allowlisted in `Rendezvous:AbuseProtection:TrustedProxyAddresses` (or indexed
+environment variables such as
+`Rendezvous__AbuseProtection__TrustedProxyAddresses__0`). Only one forwarded
+hop is accepted. With an empty allowlist, forwarded headers are ignored and the
+direct TCP peer is the source. Never add a broad network range or accept
+untrusted `X-Forwarded-For` input: that would let a caller choose its own rate
+partition.
+
+## Reflection, disclosure, and logging rules
+
+- UDP sends nothing for malformed, oversized, unauthenticated, stale,
+  replayed, wrong-role, or rate-limited input.
+- Introductions are emitted only after both role-scoped capabilities bind to
+  their observed gameplay-socket sources. HTTP never supplies a public
+  introduction target.
+- Private candidates must be same-family private unicast addresses and are used
+  only for peers observed behind the same public address.
+- Abuse keys, exceptions, and responses never include bearer credentials,
+  capabilities, tickets, raw endpoints, metadata values, or hostile markup.
+- Endpoint and capability values are not used as metric labels or log fields.
+
+## Verification
+
+The deterministic test corpora use the recorded seeds `0x152026`, `0x154A50`,
+and `0x1557A7E`. They exercise 10,000 arbitrary UDP envelopes through the
+production decoder, 5,000 arbitrary HTTP/credential parser inputs, and 1,000
+mutated state transitions, including the oversized and configured-capacity
+boundaries.
+Focused tests cover IPv4 and IPv6 prefix
+partitioning, tenant/principal/resource concurrency, tracker exhaustion,
+window recovery, wire-operation isolation, a steady-state allocation ceiling,
+typed `429`/`413` responses, secret fingerprint redaction, and silent
+authenticated UDP shedding. The existing state, contract, HTTP, client,
+and mediator suites continue to cover cross-tenant access, replay, role swaps,
+credential rotation, bounded metadata, endpoint validation, and one-shot
+amplification behavior.

docs/security/control-matrix.md

@@ -11,7 +11,7 @@ backlog where the control is implemented and verified.
 | Per-game credentials and signing keys | Provisioned principals and versioned keys are scoped to game/environment; secrets come from a provider and never a public binary. (#5) | Cross-tenant authorization tests, rotation/overlap/revocation tests, and secret scans. |
 | Short-lived, single-purpose tokens resistant to replay | Issuer fixes audience, tenant, attempt, role, issued/expiry times, nonce, and key ID; store atomically consumes nonce/ticket. (#4, #6, #10) | Golden vectors; expired, future, mutated, wrong-role, wrong-tenant, and concurrent replay tests. |
 | Strict payload, metadata, and token size limits | ADR 0003 ceilings are checked before allocation/deserialization and again at domain construction. (#4, #15) | Boundary/property tests, malformed corpus, and allocation-aware fuzzing. |
-| Registration, query, and introduction rate limits | Layered per-address, principal, tenant, and global token buckets with bounded queues and stable retry guidance. (#15) | Limit partition/isolation tests and overload/soak profiles. |
+| Registration, query, and introduction rate limits | Layered fixed-window budgets and concurrency leases cover global, operation, IPv4 `/24` or IPv6 `/56`, tenant, principal/capability, and listing/attempt dimensions with a bounded key table and stable retry guidance. (#15) | Deterministic partition, concurrency, tracker-exhaustion, recovery, typed-overload, and silent-UDP-shedding tests. |
 | Lease expiry removes abandoned servers | Visibility and join eligibility atomically require a fresh lease and fresh authenticated presence. (#6, #7) | Fake-clock expiry, renew/expire race, restart, and stale-host join tests. |
 | Validate game, environment, room, and protocol boundaries | Every identifier is a validated type; store keys and authorization decisions include server-derived tenant scope; protocol is exact-match in v1. (#4-#10) | Contract, tenant-isolation, incompatible-version, and confused-deputy tests. |
 | Structured audit events without secrets or reusable credentials | Allowlisted audit schema excludes metadata values, raw endpoints, tokens, and key material; event volume is bounded. (#16) | Captured-log/audit assertions and credential canary scans. |

docs/security/provisioning.md

@@ -63,8 +63,9 @@ only its public key ID/lifecycle metadata and does not require retired secret
 material to remain available.
 
 Key IDs are non-secret base64url identifiers. Secret references are resolved
-through `ISecretProvider`; production supports `env:<VARIABLE>` references and
-the interface is replaceable by a deployment-specific vault/KMS adapter. The
+through `ISecretProvider`; production supports base64 `env:<VARIABLE>` and raw
+`file:/absolute/path` references to bounded non-symlink files. The interface is
+replaceable by a deployment-specific vault/KMS adapter. The
 committed development profile uses an in-memory random key identified by a
 `development:ephemeral/...` reference. It never writes key material to disk and
 all credentials become invalid when the process exits.
@@ -74,8 +75,10 @@ all credentials become invalid when the process exits.
 `Rendezvous:Provisioning` supplies issuer, audience, clock skew, signing-key
 descriptors, and game policies. A production key reference such as
 `env:RENDEZVOUS_SIGNING_KEY_2026_01` expects that environment variable to hold at
-least 32 random bytes encoded as base64. Missing, malformed, short, inactive, or
-duplicate keys stop startup with a key-ID-only diagnostic. No game-wide secret
+least 32 random bytes encoded as base64. `file:/run/secrets/rendezvous-signing`
+expects the raw bytes in a read-only, absolute, non-symlink file. Missing,
+malformed, short, inactive, or duplicate keys stop startup with a key-ID-only
+diagnostic. No game-wide secret
 belongs in `appsettings`, source control, examples, the Client package, URLs,
 responses, logs, metrics, exceptions, or diagnostic dumps.
 

scripts/smoke-deployment.sh

@@ -0,0 +1,148 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+SERVICE_URL="${RENDEZVOUS_SMOKE_HTTP_URL:-http://127.0.0.1:8080/}"
+MEDIATOR="${RENDEZVOUS_SMOKE_UDP_ENDPOINT:-127.0.0.1:9050}"
+TIMEOUT_SECONDS="${RENDEZVOUS_SMOKE_TIMEOUT_SECONDS:-30}"
+LOCAL_KEY="${RENDEZVOUS_SMOKE_LOCAL_KEY:-$ROOT/deploy/compose/secrets/signing-key}"
+PROJECT="$ROOT/src/FinalFactory.Rendezvous.TestClient/FinalFactory.Rendezvous.TestClient.csproj"
+BUILD_CONFIGURATION="${RENDEZVOUS_SMOKE_CONFIGURATION:-Release}"
+GAME_ID="${RENDEZVOUS_SMOKE_GAME_ID:-space-game}"
+ENVIRONMENT_ID="${RENDEZVOUS_SMOKE_ENVIRONMENT_ID:-smoke}"
+REGION="${RENDEZVOUS_SMOKE_REGION:-local}"
+PROTOCOL_VERSION="${RENDEZVOUS_SMOKE_PROTOCOL_VERSION:-1}"
+
+for command in curl date dotnet jq mktemp od openssl tail tr wc; do
+    command -v "$command" >/dev/null || {
+        printf 'Missing required command: %s\n' "$command" >&2
+        exit 2
+    }
+done
+
+if [[ ! "$TIMEOUT_SECONDS" =~ ^[0-9]+$ ]] || (( TIMEOUT_SECONDS < 1 || TIMEOUT_SECONDS > 300 )); then
+    printf 'RENDEZVOUS_SMOKE_TIMEOUT_SECONDS must be an integer from 1 through 300.\n' >&2
+    exit 2
+fi
+if [[ ! "$PROTOCOL_VERSION" =~ ^[0-9]+$ ]] || (( PROTOCOL_VERSION < 1 )); then
+    printf 'RENDEZVOUS_SMOKE_PROTOCOL_VERSION must be a positive integer.\n' >&2
+    exit 2
+fi
+for scoped_value in "$GAME_ID" "$ENVIRONMENT_ID" "$REGION"; do
+    if [[ -z "$scoped_value" ]]; then
+        printf 'Smoke game, environment, and region values must not be empty.\n' >&2
+        exit 2
+    fi
+done
+
+base64url() {
+    openssl base64 -A | tr '+/' '-_' | tr -d '='
+}
+
+local_credential() {
+    if [[ ! -f "$LOCAL_KEY" ]] || [[ "$(wc -c < "$LOCAL_KEY")" -ne 32 ]]; then
+        printf 'Local Compose smoke key must be exactly 32 bytes: %s\n' "$LOCAL_KEY" >&2
+        exit 2
+    fi
+
+    local now expires nonce payload encoded signed hex signature
+    now="$(date +%s)"
+    expires="$((now + 600))"
+    nonce="$(openssl rand -hex 16)"
+    payload="$(jq -cn \
+        --arg issuer final-factory-rendezvous-smoke \
+        --arg audience rendezvous-service \
+        --arg subject local-smoke-host \
+        --arg kind dedicatedPublisher \
+        --arg gameId "$GAME_ID" \
+        --arg environmentId "$ENVIRONMENT_ID" \
+        --arg region "$REGION" \
+        --arg nonce "$nonce" \
+        --argjson now "$now" \
+        --argjson expires "$expires" \
+        '{version:1,issuer:$issuer,audience:$audience,subject:$subject,kind:$kind,gameId:$gameId,environmentId:$environmentId,regions:[$region],permissions:[],issuedAtUnixSeconds:$now,notBeforeUnixSeconds:$now,expiresAtUnixSeconds:$expires,nonce:$nonce}')"
+    encoded="$(printf '%s' "$payload" | base64url)"
+    signed="rv1.local-smoke-1.$encoded"
+    hex="$(od -An -v -tx1 "$LOCAL_KEY" | tr -d ' \n')"
+    signature="$(printf '%s' "$signed" \
+        | openssl dgst -sha256 -mac HMAC -macopt "hexkey:$hex" -binary \
+        | base64url)"
+    printf '%s.%s' "$signed" "$signature"
+}
+
+credential="${RENDEZVOUS_PUBLISHER_CREDENTIAL:-}"
+if [[ -z "$credential" ]]; then
+    credential="$(local_credential)"
+fi
+export RENDEZVOUS_PUBLISHER_CREDENTIAL="$credential"
+
+curl --fail --silent --show-error --max-time 5 "${SERVICE_URL%/}/health/live" >/dev/null
+curl --fail --silent --show-error --max-time 5 "${SERVICE_URL%/}/health/ready" >/dev/null
+
+temp_dir="$(mktemp -d)"
+host_log="$temp_dir/host.jsonl"
+join_log="$temp_dir/join.jsonl"
+host_pid=''
+cleanup() {
+    local status="$?"
+    if [[ -n "$host_pid" ]] && kill -0 "$host_pid" 2>/dev/null; then
+        kill -TERM "$host_pid" 2>/dev/null || true
+        wait "$host_pid" 2>/dev/null || true
+    fi
+    if [[ "$status" -ne 0 ]]; then
+        printf 'Deployment smoke failed; sanitized diagnostic events follow.\n' >&2
+        [[ -f "$host_log" ]] && jq -c . "$host_log" >&2 || true
+        [[ -f "$join_log" ]] && jq -c . "$join_log" >&2 || true
+    fi
+    rm -rf "$temp_dir"
+    return "$status"
+}
+trap cleanup EXIT
+trap 'exit 130' INT
+trap 'exit 143' TERM
+
+dotnet run --project "$PROJECT" --configuration "$BUILD_CONFIGURATION" --no-build -- \
+    host --service "$SERVICE_URL" --mediator "$MEDIATOR" \
+    --game "$GAME_ID" --environment "$ENVIRONMENT_ID" --region "$REGION" --protocol "$PROTOCOL_VERSION" \
+    --script --json --exit-after-echo --timeout-seconds "$TIMEOUT_SECONDS" \
+    >"$host_log" 2>&1 &
+host_pid="$!"
+
+ready=false
+for ((iteration = 0; iteration < TIMEOUT_SECONDS * 4; iteration++)); do
+    if jq -e 'select(.event == "host.ready")' "$host_log" >/dev/null 2>&1; then
+        ready=true
+        break
+    fi
+    if ! kill -0 "$host_pid" 2>/dev/null; then
+        printf 'Host diagnostic stopped before it became ready.\n' >&2
+        jq -c . "$host_log" >&2 || true
+        exit 1
+    fi
+    sleep 0.25
+done
+if [[ "$ready" != true ]]; then
+    printf 'Host diagnostic did not become ready within %s seconds.\n' "$TIMEOUT_SECONDS" >&2
+    exit 1
+fi
+
+listing_id="$(jq -r 'select(.event == "host.registered") | .listingId' "$host_log" | tail -n 1)"
+if [[ -z "$listing_id" || "$listing_id" == null ]]; then
+    printf 'Host diagnostic did not report a listing ID.\n' >&2
+    exit 1
+fi
+
+dotnet run --project "$PROJECT" --configuration "$BUILD_CONFIGURATION" --no-build -- \
+    join --service "$SERVICE_URL" --mediator "$MEDIATOR" \
+    --game "$GAME_ID" --environment "$ENVIRONMENT_ID" --region "$REGION" --protocol "$PROTOCOL_VERSION" \
+    --listing "$listing_id" --script --json --timeout-seconds "$TIMEOUT_SECONDS" \
+    >"$join_log" 2>&1
+wait "$host_pid"
+host_pid=''
+
+jq -e 'select(.event == "host.direct-traffic" and .status == "verified")' "$host_log" >/dev/null
+jq -e 'select(.event == "host.deregistered" and .status == "complete")' "$host_log" >/dev/null
+jq -e 'select(.event == "join.direct-traffic" and .status == "verified")' "$join_log" >/dev/null
+jq -e 'select(.event == "join.outcome-report" and .status == "accepted")' "$join_log" >/dev/null
+
+printf 'Rendezvous deployment smoke passed: HTTP live/ready and authenticated UDP mediation/direct traffic.\n'

src/FinalFactory.Rendezvous.Server/Abuse/AbuseProtectionOptions.cs

@@ -0,0 +1,111 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace FinalFactory.Rendezvous.Server.Abuse;
+
+internal sealed class AbuseProtectionOptions
+{
+    public const string SectionName = "Rendezvous:AbuseProtection";
+
+    [Range(1, 60)]
+    public int WindowSeconds { get; set; } = 1;
+
+    [Range(1_000, 1_000_000)]
+    public int MaxTrackedKeys { get; set; } = 100_000;
+
+    [Range(0, 100_000)]
+    public int CriticalTrackedKeyReserve { get; set; } = 2_048;
+
+    [Range(1_000, 999_999)]
+    public int UdpTrackedKeyLimit { get; set; } = 70_000;
+
+    public string[] TrustedProxyAddresses { get; set; } = [];
+
+    public string[] OperatorAllowedAddresses { get; set; } = [];
+
+    [Range(1, 100_000)]
+    public int HealthGlobalRequestsPerWindow { get; set; } = 1_000;
+
+    [Range(1, 10_000)]
+    public int HealthGlobalConcurrency { get; set; } = 32;
+
+    [Range(1, 100_000)]
+    public int HealthIpPrefixRequestsPerWindow { get; set; } = 120;
+
+    [Range(1, 1_000)]
+    public int HealthIpPrefixConcurrency { get; set; } = 8;
+
+    [Range(1, 100_000)]
+    public int OperatorGlobalRequestsPerWindow { get; set; } = 1_000;
+
+    [Range(1, 10_000)]
+    public int OperatorGlobalConcurrency { get; set; } = 32;
+
+    [Range(1, 100_000)]
+    public int OperatorIpPrefixRequestsPerWindow { get; set; } = 120;
+
+    [Range(1, 1_000)]
+    public int OperatorIpPrefixConcurrency { get; set; } = 8;
+
+    [Range(1, 1_000_000)]
+    public int HttpGlobalRequestsPerWindow { get; set; } = 20_000;
+
+    [Range(1, 1_000_000)]
+    public int HttpOptionalRequestsPerWindow { get; set; } = 18_000;
+
+    [Range(1, 100_000)]
+    public int HttpIpPrefixRequestsPerWindow { get; set; } = 500;
+
+    [Range(1, 100_000)]
+    public int HttpOptionalIpPrefixRequestsPerWindow { get; set; } = 450;
+
+    [Range(1, 1_000_000)]
+    public int HttpOperationRequestsPerWindow { get; set; } = 5_000;
+
+    [Range(1, 1_000_000)]
+    public int HttpTenantRequestsPerWindow { get; set; } = 2_000;
+
+    [Range(1, 100_000)]
+    public int HttpPrincipalRequestsPerWindow { get; set; } = 500;
+
+    [Range(1, 100_000)]
+    public int HttpResourceRequestsPerWindow { get; set; } = 200;
+
+    [Range(1, 100_000)]
+    public int HttpGlobalConcurrency { get; set; } = 1_024;
+
+    [Range(1, 100_000)]
+    public int HttpOptionalConcurrency { get; set; } = 768;
+
+    [Range(1, 10_000)]
+    public int HttpIpPrefixConcurrency { get; set; } = 64;
+
+    [Range(1, 10_000)]
+    public int HttpOptionalIpPrefixConcurrency { get; set; } = 48;
+
+    [Range(1, 100_000)]
+    public int HttpOperationConcurrency { get; set; } = 256;
+
+    [Range(1, 100_000)]
+    public int HttpTenantConcurrency { get; set; } = 256;
+
+    [Range(1, 10_000)]
+    public int HttpPrincipalConcurrency { get; set; } = 32;
+
+    [Range(1, 10_000)]
+    public int HttpResourceConcurrency { get; set; } = 16;
+
+    [Range(1, 10_000_000)]
+    public int UdpGlobalDatagramsPerWindow { get; set; } = 100_000;
+
+    [Range(1, 1_000_000)]
+    public int UdpIpPrefixDatagramsPerWindow { get; set; } = 2_000;
+
+    [Range(1, 10_000_000)]
+    public int UdpOperationDatagramsPerWindow { get; set; } = 50_000;
+
+    [Range(1, 100_000)]
+    public int UdpCapabilityDatagramsPerWindow { get; set; } = 120;
+
+    [Range(1, 100_000)]
+    public int UdpResourceDatagramsPerWindow { get; set; } = 240;
+}

src/FinalFactory.Rendezvous.Server/Abuse/AbuseProtectionService.cs

@@ -0,0 +1,530 @@
+using System.Buffers;
+using System.Net;
+using System.Security.Cryptography;
+using System.Text;
+using FinalFactory.Rendezvous.Server.Observability;
+using Microsoft.Extensions.Options;
+
+namespace FinalFactory.Rendezvous.Server.Abuse;
+
+internal sealed class AbuseProtectionService
+{
+    private readonly AbuseProtectionOptions _options;
+    private readonly TimeProvider _timeProvider;
+    private readonly TrackerState _httpTracker;
+    private readonly TrackerState _udpTracker;
+    private readonly RendezvousTelemetry? _telemetry;
+    private readonly HashSet<string> _operatorAllowedAddresses;
+
+    public AbuseProtectionService(
+        IOptions<AbuseProtectionOptions> options,
+        TimeProvider? timeProvider = null,
+        RendezvousTelemetry? telemetry = null)
+    {
+        _options = options.Value;
+        _timeProvider = timeProvider ?? TimeProvider.System;
+        _telemetry = telemetry;
+        _operatorAllowedAddresses = options.Value.OperatorAllowedAddresses
+            .Select(static value => IPAddress.TryParse(value, out IPAddress? address)
+                ? NormalizeAddress(address).ToString()
+                : string.Empty)
+            .Where(static value => value.Length > 0)
+            .ToHashSet(StringComparer.Ordinal);
+        DateTimeOffset now = _timeProvider.GetUtcNow();
+        _httpTracker = new(now);
+        _udpTracker = new(now);
+    }
+
+    public bool TryAcquireHttpIngress(
+        IPAddress? remoteAddress,
+        string operation,
+        out AbuseLease? lease,
+        out int retryAfterSeconds)
+    {
+        string prefix = GetNetworkPrefix(remoteAddress);
+        List<RateDimension> rates =
+        [
+            new("http:rate:global", _options.HttpGlobalRequestsPerWindow),
+            new($"http:rate:ip:{prefix}", _options.HttpIpPrefixRequestsPerWindow),
+            new($"http:rate:operation:{operation}", _options.HttpOperationRequestsPerWindow),
+        ];
+        List<RateDimension> concurrency =
+        [
+            new("http:concurrency:global", _options.HttpGlobalConcurrency),
+            new($"http:concurrency:ip:{prefix}", _options.HttpIpPrefixConcurrency),
+            new($"http:concurrency:operation:{operation}", _options.HttpOperationConcurrency),
+        ];
+        if (!IsLeaseCriticalOperation(operation))
+        {
+            rates.Add(new("http:rate:optional", _options.HttpOptionalRequestsPerWindow));
+            rates.Add(new($"http:rate:optional-ip:{prefix}",
+                _options.HttpOptionalIpPrefixRequestsPerWindow));
+            concurrency.Add(new("http:concurrency:optional", _options.HttpOptionalConcurrency));
+            concurrency.Add(new($"http:concurrency:optional-ip:{prefix}",
+                _options.HttpOptionalIpPrefixConcurrency));
+        }
+
+        return TryAcquire(
+            [.. rates],
+            [.. concurrency],
+            TrackerDomain.Http,
+            IsLeaseCriticalOperation(operation),
+            out lease,
+            out retryAfterSeconds);
+    }
+
+    public bool TryAcquireHealthIngress(
+        IPAddress? remoteAddress,
+        out AbuseLease? lease,
+        out int retryAfterSeconds)
+    {
+        string prefix = GetNetworkPrefix(remoteAddress);
+        RateDimension[] rates =
+        [
+            new("health:rate:global", _options.HealthGlobalRequestsPerWindow),
+            new($"health:rate:ip:{prefix}", _options.HealthIpPrefixRequestsPerWindow),
+        ];
+        RateDimension[] concurrency =
+        [
+            new("health:concurrency:global", _options.HealthGlobalConcurrency),
+            new($"health:concurrency:ip:{prefix}", _options.HealthIpPrefixConcurrency),
+        ];
+        return TryAcquire(
+            rates,
+            concurrency,
+            TrackerDomain.Http,
+            true,
+            out lease,
+            out retryAfterSeconds);
+    }
+
+    public bool IsOperatorSourceAllowed(IPAddress? remoteAddress) =>
+        remoteAddress is not null
+        && _operatorAllowedAddresses.Contains(NormalizeAddress(remoteAddress).ToString());
+
+    public bool TryAcquireOperatorIngress(
+        IPAddress? remoteAddress,
+        out AbuseLease? lease,
+        out int retryAfterSeconds)
+    {
+        string prefix = GetNetworkPrefix(remoteAddress);
+        RateDimension[] rates =
+        [
+            new("operator:rate:global", _options.OperatorGlobalRequestsPerWindow),
+            new($"operator:rate:ip:{prefix}", _options.OperatorIpPrefixRequestsPerWindow),
+        ];
+        RateDimension[] concurrency =
+        [
+            new("operator:concurrency:global", _options.OperatorGlobalConcurrency),
+            new($"operator:concurrency:ip:{prefix}", _options.OperatorIpPrefixConcurrency),
+        ];
+        return TryAcquire(
+            rates,
+            concurrency,
+            TrackerDomain.Http,
+            true,
+            out lease,
+            out retryAfterSeconds);
+    }
+
+    public bool TryAcquireHttpIdentity(
+        string operation,
+        string? tenant,
+        string? principal,
+        string? resource,
+        out AbuseLease? lease,
+        out int retryAfterSeconds) => TryAcquireHttpIdentity(
+        operation,
+        null,
+        tenant,
+        principal,
+        resource,
+        out lease,
+        out retryAfterSeconds);
+
+    public bool TryAcquireHttpIdentity(
+        string operation,
+        IPAddress? remoteAddress,
+        string? tenant,
+        string? principal,
+        string? resource,
+        out AbuseLease? lease,
+        out int retryAfterSeconds)
+    {
+        string sourcePrefix = GetNetworkPrefix(remoteAddress);
+        List<RateDimension> rates = [];
+        List<RateDimension> concurrency = [];
+        AddDimension(rates, concurrency, "tenant", tenant,
+            _options.HttpTenantRequestsPerWindow, _options.HttpTenantConcurrency);
+        AddDimension(rates, concurrency, "principal", principal,
+            _options.HttpPrincipalRequestsPerWindow, _options.HttpPrincipalConcurrency);
+        AddDimension(rates, concurrency, "resource", resource,
+            _options.HttpResourceRequestsPerWindow, _options.HttpResourceConcurrency);
+        return TryAcquire(
+            [.. rates],
+            [.. concurrency],
+            TrackerDomain.Http,
+            IsLeaseCriticalOperation(operation),
+            out lease,
+            out retryAfterSeconds);
+
+        void AddDimension(
+            List<RateDimension> rateDimensions,
+            List<RateDimension> concurrencyDimensions,
+            string kind,
+            string? value,
+            int rateLimit,
+            int concurrencyLimit)
+        {
+            if (string.IsNullOrEmpty(value))
+            {
+                return;
+            }
+
+            if (kind == "resource")
+            {
+                string validationKey =
+                    $"http:source-resource:{operation}:{sourcePrefix}:{value}";
+                rateDimensions.Add(new($"{validationKey}:rate", rateLimit));
+                concurrencyDimensions.Add(new($"{validationKey}:concurrency", concurrencyLimit));
+            }
+
+            string key = kind == "resource"
+                ? $"http:resource-scoped:{operation}:{tenant ?? string.Empty}|{principal ?? string.Empty}:{value}"
+                : $"http:{kind}:{operation}:{value}";
+            rateDimensions.Add(new($"{key}:rate", rateLimit));
+            concurrencyDimensions.Add(new($"{key}:concurrency", concurrencyLimit));
+        }
+    }
+
+    public bool TryAcceptUdpIngress(IPAddress? remoteAddress, string operation)
+    {
+        string prefix = GetNetworkPrefix(remoteAddress);
+        RateDimension[] rates =
+        [
+            new("udp:rate:global", _options.UdpGlobalDatagramsPerWindow),
+            new($"udp:rate:ip:{prefix}", _options.UdpIpPrefixDatagramsPerWindow),
+            new($"udp:rate:operation:{operation}", _options.UdpOperationDatagramsPerWindow),
+        ];
+        return TryAcquire(
+                   rates,
+                   [],
+                   TrackerDomain.Udp,
+                   false,
+                   out AbuseLease? lease,
+                   out _)
+               && DisposeAccepted(lease);
+    }
+
+    public bool TryAcceptUdpIdentity(
+        string operation,
+        string capability,
+        string resource) => TryAcceptUdpIdentity(
+        operation,
+        null,
+        capability,
+        resource);
+
+    public bool TryAcceptUdpIdentity(
+        string operation,
+        IPAddress? remoteAddress,
+        string capability,
+        string resource)
+    {
+        string sourcePrefix = GetNetworkPrefix(remoteAddress);
+        string capabilityFingerprint = FingerprintSecret(capability);
+        RateDimension[] rates =
+        [
+            new($"udp:rate:capability:{operation}:{capabilityFingerprint}",
+                _options.UdpCapabilityDatagramsPerWindow),
+            new($"udp:rate:source-resource:{operation}:{sourcePrefix}:{resource}",
+                _options.UdpResourceDatagramsPerWindow),
+            new($"udp:rate:resource:{operation}:{capabilityFingerprint}:{resource}",
+                _options.UdpResourceDatagramsPerWindow),
+        ];
+        return TryAcquire(
+                   rates,
+                   [],
+                   TrackerDomain.Udp,
+                   false,
+                   out AbuseLease? lease,
+                   out _)
+               && DisposeAccepted(lease);
+    }
+
+    public static string FingerprintSecret(string secret)
+    {
+        int byteCount = Encoding.UTF8.GetByteCount(secret);
+        byte[]? rented = null;
+        Span<byte> encoded = byteCount <= 1_024
+            ? stackalloc byte[byteCount]
+            : (rented = ArrayPool<byte>.Shared.Rent(byteCount)).AsSpan(0, byteCount);
+        Span<byte> digest = stackalloc byte[32];
+        try
+        {
+            _ = Encoding.UTF8.GetBytes(secret, encoded);
+            _ = SHA256.HashData(encoded, digest);
+            return Convert.ToHexString(digest[..12]);
+        }
+        finally
+        {
+            CryptographicOperations.ZeroMemory(encoded);
+            CryptographicOperations.ZeroMemory(digest);
+            if (rented is not null)
+            {
+                ArrayPool<byte>.Shared.Return(rented);
+            }
+        }
+    }
+
+    internal int TrackedKeyCount
+    {
+        get
+        {
+            int http;
+            int udp;
+            lock (_httpTracker.Gate)
+            {
+                http = _httpTracker.WindowCounts.Count + _httpTracker.ConcurrencyCounts.Count;
+            }
+
+            lock (_udpTracker.Gate)
+            {
+                udp = _udpTracker.WindowCounts.Count + _udpTracker.ConcurrencyCounts.Count;
+            }
+
+            return http + udp;
+        }
+    }
+
+    private bool TryAcquire(
+        ReadOnlySpan<RateDimension> rates,
+        ReadOnlySpan<RateDimension> concurrency,
+        TrackerDomain domain,
+        bool canUseCriticalReserve,
+        out AbuseLease? lease,
+        out int retryAfterSeconds)
+    {
+        TrackerState tracker = domain == TrackerDomain.Udp ? _udpTracker : _httpTracker;
+        bool accepted;
+        lock (tracker.Gate)
+        {
+            accepted = TryAcquireLocked(
+                tracker,
+                rates,
+                concurrency,
+                domain,
+                canUseCriticalReserve,
+                out lease,
+                out retryAfterSeconds);
+        }
+
+        if (!accepted)
+        {
+            _telemetry?.RecordLimiterDrop(
+                domain == TrackerDomain.Udp ? "udp" : "http",
+                "rate-or-concurrency");
+        }
+
+        return accepted;
+    }
+
+    private bool TryAcquireLocked(
+        TrackerState tracker,
+        ReadOnlySpan<RateDimension> rates,
+        ReadOnlySpan<RateDimension> concurrency,
+        TrackerDomain domain,
+        bool canUseCriticalReserve,
+        out AbuseLease? lease,
+        out int retryAfterSeconds)
+    {
+        DateTimeOffset now = _timeProvider.GetUtcNow();
+        TimeSpan window = TimeSpan.FromSeconds(_options.WindowSeconds);
+        if (now - tracker.WindowStartedAt >= window || now < tracker.WindowStartedAt)
+        {
+            tracker.WindowCounts.Clear();
+            tracker.WindowStartedAt = now;
+        }
+
+        retryAfterSeconds = Math.Max(
+            1,
+            (int)Math.Ceiling((window - (now - tracker.WindowStartedAt)).TotalSeconds));
+        int stagedNewKeys = 0;
+        int partitionLimit = domain == TrackerDomain.Udp
+            ? _options.UdpTrackedKeyLimit
+            : _options.MaxTrackedKeys - _options.UdpTrackedKeyLimit;
+        int maxTrackedKeys = domain == TrackerDomain.Udp || canUseCriticalReserve
+            ? partitionLimit
+            : partitionLimit - _options.CriticalTrackedKeyReserve;
+        if (!CanAcquireAll(
+                tracker,
+                tracker.WindowCounts,
+                rates,
+                maxTrackedKeys,
+                ref stagedNewKeys)
+            || !CanAcquireAll(
+                tracker,
+                tracker.ConcurrencyCounts,
+                concurrency,
+                maxTrackedKeys,
+                ref stagedNewKeys))
+        {
+            lease = null;
+            return false;
+        }
+
+        foreach (RateDimension dimension in rates)
+        {
+            tracker.WindowCounts[dimension.Key] =
+                tracker.WindowCounts.GetValueOrDefault(dimension.Key) + 1;
+        }
+
+        if (concurrency.IsEmpty)
+        {
+            lease = null;
+            return true;
+        }
+
+        string[] acquiredConcurrency = new string[concurrency.Length];
+        for (int index = 0; index < concurrency.Length; index++)
+        {
+            RateDimension dimension = concurrency[index];
+            tracker.ConcurrencyCounts[dimension.Key] =
+                tracker.ConcurrencyCounts.GetValueOrDefault(dimension.Key) + 1;
+            acquiredConcurrency[index] = dimension.Key;
+        }
+
+        lease = new AbuseLease(this, tracker, acquiredConcurrency);
+        return true;
+    }
+
+    private static bool CanAcquireAll(
+        TrackerState tracker,
+        Dictionary<string, int> counts,
+        ReadOnlySpan<RateDimension> dimensions,
+        int maxTrackedKeys,
+        ref int stagedNewKeys)
+    {
+        foreach (RateDimension dimension in dimensions)
+        {
+            if (counts.TryGetValue(dimension.Key, out int current))
+            {
+                if (current >= dimension.Limit)
+                {
+                    return false;
+                }
+
+                continue;
+            }
+
+            stagedNewKeys++;
+            if (tracker.WindowCounts.Count + tracker.ConcurrencyCounts.Count + stagedNewKeys
+                > maxTrackedKeys)
+            {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    private static void Release(TrackerState tracker, string[] keys)
+    {
+        lock (tracker.Gate)
+        {
+            foreach (string key in keys)
+            {
+                if (!tracker.ConcurrencyCounts.TryGetValue(key, out int current))
+                {
+                    continue;
+                }
+
+                if (current <= 1)
+                {
+                    tracker.ConcurrencyCounts.Remove(key);
+                }
+                else
+                {
+                    tracker.ConcurrencyCounts[key] = current - 1;
+                }
+            }
+        }
+    }
+
+    private static bool DisposeAccepted(AbuseLease? lease)
+    {
+        lease?.Dispose();
+        return true;
+    }
+
+    private static bool IsLeaseCriticalOperation(string operation) => operation is
+        "RenewSessionLease" or "UpdateSession" or "DeleteSession";
+
+    private static string GetNetworkPrefix(IPAddress? address)
+    {
+        if (address is null)
+        {
+            return "unknown";
+        }
+
+        IPAddress normalized = address.IsIPv4MappedToIPv6 ? address.MapToIPv4() : address;
+        byte[] bytes = normalized.GetAddressBytes();
+        if (bytes.Length == 4)
+        {
+            bytes[3] = 0;
+            return $"4:{Convert.ToHexString(bytes)}:24";
+        }
+
+        if (bytes.Length == 16)
+        {
+            Array.Clear(bytes, 7, 9);
+            return $"6:{Convert.ToHexString(bytes)}:56";
+        }
+
+        return "unknown";
+    }
+
+    private static IPAddress NormalizeAddress(IPAddress address) =>
+        address.IsIPv4MappedToIPv6 ? address.MapToIPv4() : address;
+
+    private readonly record struct RateDimension(string Key, int Limit);
+
+    private enum TrackerDomain
+    {
+        Http,
+        Udp,
+    }
+
+    internal sealed class TrackerState(DateTimeOffset windowStartedAt)
+    {
+        public object Gate { get; } = new();
+        public Dictionary<string, int> WindowCounts { get; } = new(StringComparer.Ordinal);
+        public Dictionary<string, int> ConcurrencyCounts { get; } = new(StringComparer.Ordinal);
+        public DateTimeOffset WindowStartedAt { get; set; } = windowStartedAt;
+    }
+
+    internal sealed class AbuseLease : IDisposable
+    {
+        private AbuseProtectionService? _owner;
+        private readonly TrackerState _tracker;
+        private readonly string[] _keys;
+
+        internal AbuseLease(
+            AbuseProtectionService owner,
+            TrackerState tracker,
+            string[] keys)
+        {
+            _owner = owner;
+            _tracker = tracker;
+            _keys = keys;
+        }
+
+        public void Dispose()
+        {
+            if (Interlocked.Exchange(ref _owner, null) is not null)
+            {
+                Release(_tracker, _keys);
+            }
+        }
+    }
+}

src/FinalFactory.Rendezvous.Server/Abuse/HttpAbuseProtectionMiddleware.cs

@@ -0,0 +1,135 @@
+using FinalFactory.Rendezvous.Contracts;
+using Microsoft.AspNetCore.Http.Features;
+
+namespace FinalFactory.Rendezvous.Server.Abuse;
+
+internal sealed class HttpAbuseProtectionMiddleware(
+    RequestDelegate next,
+    AbuseProtectionService protection)
+{
+    public async Task InvokeAsync(HttpContext context)
+    {
+        IHttpMaxRequestBodySizeFeature? bodySize =
+            context.Features.Get<IHttpMaxRequestBodySizeFeature>();
+        if (bodySize is { IsReadOnly: false })
+        {
+            bodySize.MaxRequestBodySize = ContractLimits.HttpRequestMaxBytes;
+        }
+
+        string operation = context.GetEndpoint()?.Metadata.GetMetadata<IEndpointNameMetadata>()
+            ?.EndpointName ?? "Unmatched";
+        bool healthEndpoint = operation is "GetLiveness" or "GetReadiness";
+        bool operatorEndpoint = operation is
+            "GetOperatorStatus"
+            or "RevokeOperatorListing"
+            or "RevokeOperatorPrincipal"
+            or "RevokeOperatorSigningKey"
+            or "BeginOperatorDrain";
+        if (operatorEndpoint
+            && !protection.IsOperatorSourceAllowed(context.Connection.RemoteIpAddress))
+        {
+            bool deniedSourceAdmitted = protection.TryAcquireHttpIngress(
+                context.Connection.RemoteIpAddress,
+                "Unmatched",
+                out AbuseProtectionService.AbuseLease? deniedSourceLease,
+                out int deniedRetryAfterSeconds);
+            using (deniedSourceLease)
+            {
+                if (!deniedSourceAdmitted)
+                {
+                    context.Response.Headers.RetryAfter = deniedRetryAfterSeconds.ToString(
+                        System.Globalization.CultureInfo.InvariantCulture);
+                    await WriteErrorAsync(
+                        context,
+                        StatusCodes.Status429TooManyRequests,
+                        RendezvousErrorCode.RateLimited,
+                        "The request rate limit was exceeded.",
+                        deniedRetryAfterSeconds).ConfigureAwait(false);
+                    return;
+                }
+
+                await WriteErrorAsync(
+                    context,
+                    StatusCodes.Status404NotFound,
+                    RendezvousErrorCode.NotFound,
+                    "The requested resource was not found.").ConfigureAwait(false);
+            }
+
+            return;
+        }
+
+        AbuseProtectionService.AbuseLease? lease;
+        int retryAfterSeconds;
+        bool acquired;
+        if (healthEndpoint)
+        {
+            acquired = protection.TryAcquireHealthIngress(
+                context.Connection.RemoteIpAddress,
+                out lease,
+                out retryAfterSeconds);
+        }
+        else if (operatorEndpoint)
+        {
+            acquired = protection.TryAcquireOperatorIngress(
+                context.Connection.RemoteIpAddress,
+                out lease,
+                out retryAfterSeconds);
+        }
+        else
+        {
+            acquired = protection.TryAcquireHttpIngress(
+                context.Connection.RemoteIpAddress,
+                operation,
+                out lease,
+                out retryAfterSeconds);
+        }
+
+        if (!acquired)
+        {
+            context.Response.Headers.RetryAfter = retryAfterSeconds.ToString(
+                System.Globalization.CultureInfo.InvariantCulture);
+            await WriteErrorAsync(
+                context,
+                StatusCodes.Status429TooManyRequests,
+                RendezvousErrorCode.RateLimited,
+                "The request rate limit was exceeded.",
+                retryAfterSeconds).ConfigureAwait(false);
+            return;
+        }
+
+        using (lease)
+        {
+            if (context.Request.ContentLength > ContractLimits.HttpRequestMaxBytes)
+            {
+                await WriteErrorAsync(
+                    context,
+                    StatusCodes.Status413PayloadTooLarge,
+                    RendezvousErrorCode.InvalidRequest,
+                    "The request body exceeds the supported size.").ConfigureAwait(false);
+                return;
+            }
+
+            await next(context).ConfigureAwait(false);
+        }
+    }
+
+    private static Task WriteErrorAsync(
+        HttpContext context,
+        int status,
+        RendezvousErrorCode code,
+        string message,
+        int? retryAfterSeconds = null)
+    {
+        context.Response.StatusCode = status;
+        return context.Response.WriteAsJsonAsync(
+            new ApiError
+            {
+                Code = code,
+                Message = message,
+                RetryAfterSeconds = retryAfterSeconds,
+            },
+            ContractJson.Options,
+            contentType: "application/json",
+            cancellationToken: context.RequestAborted);
+    }
+}

src/FinalFactory.Rendezvous.Server/Abuse/TrustedProxyForwarding.cs

@@ -0,0 +1,24 @@
+using System.Net;
+using Microsoft.AspNetCore.HttpOverrides;
+
+namespace FinalFactory.Rendezvous.Server.Abuse;
+
+internal static class TrustedProxyForwarding
+{
+    public static bool IsEnabled(AbuseProtectionOptions options) =>
+        options.TrustedProxyAddresses is { Length: > 0 };
+
+    public static void Configure(
+        ForwardedHeadersOptions forwarded,
+        AbuseProtectionOptions abuse)
+    {
+        forwarded.ForwardedHeaders = ForwardedHeaders.XForwardedFor;
+        forwarded.ForwardLimit = 1;
+        forwarded.KnownProxies.Clear();
+        forwarded.KnownIPNetworks.Clear();
+        foreach (string address in abuse.TrustedProxyAddresses ?? [])
+        {
+            forwarded.KnownProxies.Add(IPAddress.Parse(address));
+        }
+    }
+}

src/FinalFactory.Rendezvous.Server/ConnectionOutcomes/ConnectionOutcomeService.cs

@@ -1,4 +1,5 @@
 using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Observability;
 using FinalFactory.Rendezvous.Server.Sessions;
 using FinalFactory.Rendezvous.Server.State;
 
@@ -15,6 +16,10 @@ internal sealed class ConnectionOutcomeMetrics
 {
     private readonly object _gate = new();
     private readonly Dictionary<(ConnectionOutcomeKind, ConnectionElapsedBucket), long> _counts = [];
+    private readonly RendezvousTelemetry? _telemetry;
+
+    public ConnectionOutcomeMetrics(RendezvousTelemetry? telemetry = null) =>
+        _telemetry = telemetry;
 
     internal void Record(ConnectionOutcomeKind outcome, ConnectionElapsedBucket elapsedBucket)
     {
@@ -24,6 +29,8 @@ internal sealed class ConnectionOutcomeMetrics
             _counts.TryGetValue(key, out long count);
             _counts[key] = count + 1;
         }
+
+        _telemetry?.RecordConnectionOutcome(outcome.ToString(), elapsedBucket.ToString());
     }
 
     internal long GetCount(ConnectionOutcomeKind outcome, ConnectionElapsedBucket elapsedBucket)

src/FinalFactory.Rendezvous.Server/Deployment/DeploymentOptions.cs

@@ -0,0 +1,235 @@
+using System.ComponentModel.DataAnnotations;
+using System.Net;
+using FinalFactory.Rendezvous.Server.Abuse;
+
+namespace FinalFactory.Rendezvous.Server.Deployment;
+
+internal sealed record DeploymentOptions
+{
+    public const string SectionName = "Rendezvous:Deployment";
+
+    [Required]
+    public string PublicHttpBaseUrl { get; init; } = string.Empty;
+
+    [Required]
+    public string PublicUdpHost { get; init; } = string.Empty;
+
+    [Range(1, 65_535)]
+    public int PublicUdpPort { get; init; } = 9050;
+
+    [Range(1, 30)]
+    public int DrainDeadlineSeconds { get; init; } = 30;
+
+    [Range(0, 5)]
+    public int MinimumDrainSeconds { get; init; } = 1;
+
+    public bool SingleActiveInstance { get; init; } = true;
+
+    public bool AllowPrivatePublicEndpoints { get; init; }
+
+    public IReadOnlyList<string> ValidateProduction(
+        AbuseProtectionOptions abuseProtection,
+        string? allowedHosts)
+    {
+        List<string> errors = [];
+        if (!SingleActiveInstance)
+        {
+            errors.Add("Rendezvous:Deployment:SingleActiveInstance must be true because ephemeral state is not shared between replicas.");
+        }
+
+        if (MinimumDrainSeconds >= DrainDeadlineSeconds)
+        {
+            errors.Add("Rendezvous:Deployment:MinimumDrainSeconds must be less than DrainDeadlineSeconds.");
+        }
+
+        if (DrainDeadlineSeconds is < 1 or > 30)
+        {
+            errors.Add("Rendezvous:Deployment:DrainDeadlineSeconds must be between 1 and 30.");
+        }
+
+        if (MinimumDrainSeconds is < 0 or > 5)
+        {
+            errors.Add("Rendezvous:Deployment:MinimumDrainSeconds must be between 0 and 5.");
+        }
+
+        if (PublicUdpPort is < 1 or > 65_535)
+        {
+            errors.Add("Rendezvous:Deployment:PublicUdpPort must be between 1 and 65535.");
+        }
+
+        ValidateHttpEndpoint(errors);
+        ValidateUdpEndpoint(errors);
+        ValidateAllowedHosts(errors, allowedHosts, PublicHttpBaseUrl);
+
+        if (abuseProtection.TrustedProxyAddresses is not { Length: > 0 })
+        {
+            errors.Add(
+                "Rendezvous:AbuseProtection:TrustedProxyAddresses must list the exact TLS proxy addresses; forwarded headers are rejected without this trust boundary.");
+        }
+
+        return errors;
+    }
+
+    private void ValidateHttpEndpoint(List<string> errors)
+    {
+        if (!Uri.TryCreate(PublicHttpBaseUrl, UriKind.Absolute, out Uri? endpoint)
+            || !string.Equals(endpoint.Scheme, Uri.UriSchemeHttps, StringComparison.Ordinal)
+            || !string.IsNullOrEmpty(endpoint.UserInfo)
+            || !string.IsNullOrEmpty(endpoint.Query)
+            || !string.IsNullOrEmpty(endpoint.Fragment)
+            || endpoint.AbsolutePath != "/")
+        {
+            errors.Add(
+                "Rendezvous:Deployment:PublicHttpBaseUrl must be an absolute HTTPS origin with no credentials, path, query, or fragment (for example, https://rendezvous.your-company.tld/).");
+            return;
+        }
+
+        if (!AllowPrivatePublicEndpoints && !IsPublicHost(endpoint.Host))
+        {
+            errors.Add(
+                "Rendezvous:Deployment:PublicHttpBaseUrl must use a public DNS name or address; set AllowPrivatePublicEndpoints=true only for an isolated deployment smoke test.");
+        }
+    }
+
+    private void ValidateUdpEndpoint(List<string> errors)
+    {
+        if (string.IsNullOrWhiteSpace(PublicUdpHost)
+            || PublicUdpHost.Contains("//", StringComparison.Ordinal)
+            || PublicUdpHost.Contains(':', StringComparison.Ordinal) && !IPAddress.TryParse(PublicUdpHost, out _)
+            || Uri.CheckHostName(PublicUdpHost) == UriHostNameType.Unknown)
+        {
+            errors.Add(
+                "Rendezvous:Deployment:PublicUdpHost must contain only the advertised DNS name or IP address; configure the port separately.");
+            return;
+        }
+
+        if (!AllowPrivatePublicEndpoints && !IsPublicHost(PublicUdpHost))
+        {
+            errors.Add(
+                "Rendezvous:Deployment:PublicUdpHost must use a public DNS name or address; set AllowPrivatePublicEndpoints=true only for an isolated deployment smoke test.");
+        }
+    }
+
+    private static void ValidateAllowedHosts(
+        List<string> errors,
+        string? allowedHosts,
+        string publicHttpBaseUrl)
+    {
+        string[] hosts = (allowedHosts ?? string.Empty).Split(
+            ';',
+            StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+        if (hosts.Length == 0 || hosts.Any(static host => host is "*" or "+"))
+        {
+            errors.Add(
+                "AllowedHosts must explicitly list the public HTTP host in production; wildcard or empty host filtering is unsafe.");
+            return;
+        }
+
+        if (Uri.TryCreate(publicHttpBaseUrl, UriKind.Absolute, out Uri? endpoint)
+            && !hosts.Contains(endpoint.Host, StringComparer.OrdinalIgnoreCase))
+        {
+            errors.Add(
+                "AllowedHosts must contain the exact host advertised by Rendezvous:Deployment:PublicHttpBaseUrl.");
+        }
+    }
+
+    private static bool IsPublicHost(string host)
+    {
+        if (!IPAddress.TryParse(host, out IPAddress? address))
+        {
+            return Uri.CheckHostName(host) == UriHostNameType.Dns
+                && host.Contains('.', StringComparison.Ordinal)
+                && !IsReservedDnsName(host);
+        }
+
+        return IsGloballyRoutableUnicast(address);
+    }
+
+    private static bool IsReservedDnsName(string host)
+    {
+        string normalized = host.TrimEnd('.');
+        string[] reservedSuffixes =
+        [
+            "localhost",
+            "local",
+            "invalid",
+            "test",
+            "example",
+            "example.com",
+            "example.net",
+            "example.org",
+            "home.arpa",
+            "alt",
+            "onion",
+        ];
+        return reservedSuffixes.Any(suffix =>
+            string.Equals(normalized, suffix, StringComparison.OrdinalIgnoreCase)
+            || normalized.EndsWith($".{suffix}", StringComparison.OrdinalIgnoreCase));
+    }
+
+    private static bool IsGloballyRoutableUnicast(IPAddress address)
+    {
+        if (address.IsIPv4MappedToIPv6)
+        {
+            address = address.MapToIPv4();
+        }
+
+        byte[] bytes = address.GetAddressBytes();
+        if (address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
+        {
+            return !(bytes[0] is 0 or 10 or 127
+                || bytes[0] == 100 && bytes[1] is >= 64 and <= 127
+                || bytes[0] == 169 && bytes[1] == 254
+                || bytes[0] == 172 && bytes[1] is >= 16 and <= 31
+                || bytes[0] == 192
+                    && (bytes[1] == 0 && bytes[2] is 0 or 2
+                        || bytes[1] == 88 && bytes[2] == 99
+                        || bytes[1] == 168)
+                || bytes[0] == 198
+                    && (bytes[1] is 18 or 19
+                        || bytes[1] == 51 && bytes[2] == 100)
+                || bytes[0] == 203 && bytes[1] == 0 && bytes[2] == 113
+                || bytes[0] >= 224);
+        }
+
+        return address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetworkV6
+            && !IPAddress.IsLoopback(address)
+            && !address.Equals(IPAddress.IPv6Any)
+            && !address.IsIPv6LinkLocal
+            && !address.IsIPv6SiteLocal
+            && !address.IsIPv6Multicast
+            && (bytes[0] & 0xe0) == 0x20
+            && !HasPrefix(bytes, [0x20, 0x01, 0x00], 23)
+            && !HasPrefix(bytes, [0x20, 0x01, 0x0d, 0xb8], 32)
+            && !HasPrefix(bytes, [0x20, 0x02], 16)
+            && !HasPrefix(bytes, [0x3f, 0xff, 0x00], 20);
+    }
+
+    private static bool HasPrefix(byte[] address, byte[] prefix, int bitCount)
+    {
+        int fullBytes = bitCount / 8;
+        for (int index = 0; index < fullBytes; index++)
+        {
+            if (address[index] != prefix[index])
+            {
+                return false;
+            }
+        }
+
+        int remainingBits = bitCount % 8;
+        if (remainingBits == 0)
+        {
+            return true;
+        }
+
+        int mask = 0xff << (8 - remainingBits);
+        return (address[fullBytes] & mask) == (prefix[fullBytes] & mask);
+    }
+}
+
+internal sealed class DeploymentConfigurationException(IReadOnlyList<string> errors)
+    : InvalidOperationException(
+        "Production deployment configuration is invalid:" + Environment.NewLine
+        + string.Join(Environment.NewLine, errors.Select(static error => $"- {error}")))
+{
+}

src/FinalFactory.Rendezvous.Server/Deployment/GracefulDrainService.cs

@@ -0,0 +1,98 @@
+using System.Diagnostics;
+using FinalFactory.Rendezvous.Server.State;
+using Microsoft.Extensions.Options;
+
+namespace FinalFactory.Rendezvous.Server.Deployment;
+
+internal sealed partial class GracefulDrainService : IHostedService, IDisposable
+{
+    private static readonly TimeSpan PollInterval = TimeSpan.FromMilliseconds(50);
+    private readonly InMemoryEphemeralRendezvousStore _store;
+    private readonly IHostApplicationLifetime _lifetime;
+    private readonly DeploymentOptions _options;
+    private readonly ILogger<GracefulDrainService> _logger;
+    private readonly object _gate = new();
+    private CancellationTokenRegistration _stoppingRegistration;
+    private Task? _drainTask;
+
+    public GracefulDrainService(
+        InMemoryEphemeralRendezvousStore store,
+        IHostApplicationLifetime lifetime,
+        IOptions<DeploymentOptions> options,
+        ILogger<GracefulDrainService> logger)
+    {
+        _store = store;
+        _lifetime = lifetime;
+        _options = options.Value;
+        _logger = logger;
+    }
+
+    public Task StartAsync(CancellationToken cancellationToken)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        _stoppingRegistration = _lifetime.ApplicationStopping.Register(
+            () => EnsureDrainAsync().GetAwaiter().GetResult());
+        return Task.CompletedTask;
+    }
+
+    public Task StopAsync(CancellationToken cancellationToken)
+    {
+        // ApplicationStopping callbacks run before hosted services and listeners
+        // stop. StopAsync is the idempotent fallback for directly driven hosts.
+        _ = cancellationToken;
+        return EnsureDrainAsync();
+    }
+
+    public void Dispose() => _stoppingRegistration.Dispose();
+
+    private Task EnsureDrainAsync()
+    {
+        lock (_gate)
+        {
+            return _drainTask ??= DrainAsync();
+        }
+    }
+
+    private async Task DrainAsync()
+    {
+        _store.BeginDrain(CancellationToken.None);
+        TimeSpan deadline = TimeSpan.FromSeconds(_options.DrainDeadlineSeconds);
+        TimeSpan minimum = TimeSpan.FromSeconds(_options.MinimumDrainSeconds);
+        long startedAt = Stopwatch.GetTimestamp();
+        LogDrainStarted(_logger, _options.DrainDeadlineSeconds);
+        try
+        {
+            while (Stopwatch.GetElapsedTime(startedAt) < deadline)
+            {
+                TimeSpan elapsed = Stopwatch.GetElapsedTime(startedAt);
+                if (elapsed >= minimum && _store.GetActiveJoinAttemptCountForDrain() == 0)
+                {
+                    break;
+                }
+
+                TimeSpan remaining = deadline - elapsed;
+                await Task.Delay(
+                    remaining < PollInterval ? remaining : PollInterval,
+                    CancellationToken.None).ConfigureAwait(false);
+            }
+        }
+        finally
+        {
+            _store.MarkUnavailable();
+            double elapsedMilliseconds = Stopwatch.GetElapsedTime(startedAt).TotalMilliseconds;
+            LogDrainFinished(_logger, elapsedMilliseconds);
+        }
+    }
+
+    [LoggerMessage(
+        EventId = 1,
+        Level = LogLevel.Information,
+        Message = "Graceful drain started with a {DrainDeadlineSeconds}-second deadline")]
+    private static partial void LogDrainStarted(ILogger logger, int drainDeadlineSeconds);
+
+    [LoggerMessage(
+        EventId = 2,
+        Level = LogLevel.Information,
+        Message = "Graceful drain finished after {ElapsedMilliseconds:F0} ms; ephemeral state was cleared")]
+    private static partial void LogDrainFinished(ILogger logger, double elapsedMilliseconds);
+}

src/FinalFactory.Rendezvous.Server/Http/ContractEndpoints.cs

@@ -1,5 +1,6 @@
 using System.Net;
 using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Abuse;
 using FinalFactory.Rendezvous.Server.Browser;
 using FinalFactory.Rendezvous.Server.ConnectionOutcomes;
 using FinalFactory.Rendezvous.Server.JoinAttempts;
@@ -20,6 +21,7 @@ internal static class ContractEndpoints
             .Accepts<RegisterSessionRequest>("application/json")
             .Produces<RegisterSessionResponse>(StatusCodes.Status201Created)
             .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status413PayloadTooLarge)
             .Produces<ApiError>(StatusCodes.Status401Unauthorized)
             .Produces<ApiError>(StatusCodes.Status403Forbidden)
             .Produces<ApiError>(StatusCodes.Status409Conflict)
@@ -31,45 +33,54 @@ internal static class ContractEndpoints
             .Accepts<RenewLeaseRequest>("application/json")
             .Produces<RenewLeaseResponse>()
             .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status413PayloadTooLarge)
             .Produces<ApiError>(StatusCodes.Status401Unauthorized)
             .Produces<ApiError>(StatusCodes.Status403Forbidden)
             .Produces<ApiError>(StatusCodes.Status404NotFound)
             .Produces<ApiError>(StatusCodes.Status409Conflict)
             .Produces<ApiError>(StatusCodes.Status410Gone)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
             .Produces<ApiError>(StatusCodes.Status503ServiceUnavailable)
             .WithName("RenewSessionLease");
         sessions.MapPut("/{listingId}", UpdateSession)
             .Accepts<UpdateSessionRequest>("application/json")
             .Produces(StatusCodes.Status204NoContent)
             .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status413PayloadTooLarge)
             .Produces<ApiError>(StatusCodes.Status401Unauthorized)
             .Produces<ApiError>(StatusCodes.Status403Forbidden)
             .Produces<ApiError>(StatusCodes.Status404NotFound)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
             .Produces<ApiError>(StatusCodes.Status503ServiceUnavailable)
             .WithName("UpdateSession");
         sessions.MapDelete("/{listingId}", DeleteSession)
             .Accepts<DeleteSessionRequest>("application/json")
             .Produces(StatusCodes.Status204NoContent)
             .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status413PayloadTooLarge)
             .Produces<ApiError>(StatusCodes.Status401Unauthorized)
             .Produces<ApiError>(StatusCodes.Status403Forbidden)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
             .Produces<ApiError>(StatusCodes.Status503ServiceUnavailable)
             .WithName("DeleteSession");
         sessions.MapGet("/", BrowseSessions)
             .Produces<BrowseSessionsResponse>()
             .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
             .Produces<ApiError>(StatusCodes.Status503ServiceUnavailable)
             .WithName("BrowseSessions");
         sessions.MapGet("/{listingId}", GetSession)
             .Produces<GetSessionResponse>()
             .Produces<ApiError>(StatusCodes.Status400BadRequest)
             .Produces<ApiError>(StatusCodes.Status404NotFound)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
             .Produces<ApiError>(StatusCodes.Status503ServiceUnavailable)
             .WithName("GetSession");
         sessions.MapGet("/{listingId}/join-attempts", BrowseHostJoinAttempts)
             .Produces<BrowseHostJoinAttemptsResponse>()
             .Produces<ApiError>(StatusCodes.Status400BadRequest)
             .Produces<ApiError>(StatusCodes.Status404NotFound)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
             .Produces<ApiError>(StatusCodes.Status503ServiceUnavailable)
             .WithName("BrowseHostJoinAttempts");
 
@@ -80,6 +91,7 @@ internal static class ContractEndpoints
             .Accepts<CreateJoinAttemptRequest>("application/json")
             .Produces<CreateJoinAttemptResponse>(StatusCodes.Status201Created)
             .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status413PayloadTooLarge)
             .Produces<ApiError>(StatusCodes.Status404NotFound)
             .Produces<ApiError>(StatusCodes.Status409Conflict)
             .Produces<ApiError>(StatusCodes.Status410Gone)
@@ -90,14 +102,17 @@ internal static class ContractEndpoints
             .Produces(StatusCodes.Status204NoContent)
             .Produces<ApiError>(StatusCodes.Status400BadRequest)
             .Produces<ApiError>(StatusCodes.Status404NotFound)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
             .Produces<ApiError>(StatusCodes.Status503ServiceUnavailable)
             .WithName("CancelJoinAttempt");
         attempts.MapPost("/{attemptId}/outcome", ReportConnectionOutcome)
             .Accepts<ReportConnectionOutcomeRequest>("application/json")
             .Produces<ReportConnectionOutcomeResponse>()
             .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status413PayloadTooLarge)
             .Produces<ApiError>(StatusCodes.Status404NotFound)
             .Produces<ApiError>(StatusCodes.Status409Conflict)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
             .Produces<ApiError>(StatusCodes.Status503ServiceUnavailable)
             .WithName("ReportConnectionOutcome");
 
@@ -109,6 +124,7 @@ internal static class ContractEndpoints
         [FromHeader(Name = "Authorization")] string? authorizationHeader,
         [FromServices] PrincipalCredentialService credentials,
         [FromServices] SessionLeaseService sessions,
+        [FromServices] AbuseProtectionService abuseProtection,
         [FromServices] IWallClock clock,
         HttpContext httpContext,
         CancellationToken cancellationToken)
@@ -122,6 +138,21 @@ internal static class ContractEndpoints
             return AuthenticationRequired(httpContext);
         }
 
+        IPublisherPrincipal publisher = (IPublisherPrincipal)principal!;
+        if (!TryAcquireIdentity(
+                abuseProtection,
+                httpContext,
+                "RegisterSession",
+                Tenant(publisher.GameId, publisher.EnvironmentId),
+                publisher.Subject,
+                null,
+                out AbuseProtectionService.AbuseLease? abuseLease))
+        {
+            return RateLimited(httpContext);
+        }
+
+        using (abuseLease)
+        {
             SessionServiceResult<RegisterSessionResponse> result = sessions.Register(
                 principal!,
                 request,
@@ -130,6 +161,7 @@ internal static class ContractEndpoints
                 ? Results.Created($"/v1/sessions/{result.Value.ListingId}", result.Value)
                 : Error(result.Error);
         }
+    }
 
     private static IResult RenewLease(
         SessionListingId listingId,
@@ -137,6 +169,7 @@ internal static class ContractEndpoints
         [FromHeader(Name = "Authorization")] string? authorizationHeader,
         [FromServices] PrincipalCredentialService credentials,
         [FromServices] SessionLeaseService sessions,
+        [FromServices] AbuseProtectionService abuseProtection,
         [FromServices] IWallClock clock,
         HttpContext httpContext,
         CancellationToken cancellationToken)
@@ -150,6 +183,21 @@ internal static class ContractEndpoints
             return AuthenticationRequired(httpContext);
         }
 
+        IPublisherPrincipal publisher = (IPublisherPrincipal)principal!;
+        if (!TryAcquireIdentity(
+                abuseProtection,
+                httpContext,
+                "RenewSessionLease",
+                Tenant(publisher.GameId, publisher.EnvironmentId),
+                publisher.Subject,
+                listingId.ToString(),
+                out AbuseProtectionService.AbuseLease? abuseLease))
+        {
+            return RateLimited(httpContext);
+        }
+
+        using (abuseLease)
+        {
             SessionServiceResult<RenewLeaseResponse> result = sessions.Renew(
                 principal!,
                 listingId,
@@ -159,6 +207,7 @@ internal static class ContractEndpoints
                 ? Results.Ok(result.Value)
                 : Error(result.Error);
         }
+    }
 
     private static IResult UpdateSession(
         SessionListingId listingId,
@@ -166,6 +215,7 @@ internal static class ContractEndpoints
         [FromHeader(Name = "Authorization")] string? authorizationHeader,
         [FromServices] PrincipalCredentialService credentials,
         [FromServices] SessionLeaseService sessions,
+        [FromServices] AbuseProtectionService abuseProtection,
         [FromServices] IWallClock clock,
         HttpContext httpContext,
         CancellationToken cancellationToken)
@@ -179,6 +229,21 @@ internal static class ContractEndpoints
             return AuthenticationRequired(httpContext);
         }
 
+        IPublisherPrincipal publisher = (IPublisherPrincipal)principal!;
+        if (!TryAcquireIdentity(
+                abuseProtection,
+                httpContext,
+                "UpdateSession",
+                Tenant(publisher.GameId, publisher.EnvironmentId),
+                publisher.Subject,
+                listingId.ToString(),
+                out AbuseProtectionService.AbuseLease? abuseLease))
+        {
+            return RateLimited(httpContext);
+        }
+
+        using (abuseLease)
+        {
             SessionServiceResult<bool> result = sessions.Update(
                 principal!,
                 listingId,
@@ -186,6 +251,7 @@ internal static class ContractEndpoints
                 cancellationToken);
             return result.Succeeded ? Results.NoContent() : Error(result.Error);
         }
+    }
 
     private static IResult DeleteSession(
         SessionListingId listingId,
@@ -193,6 +259,7 @@ internal static class ContractEndpoints
         [FromHeader(Name = "Authorization")] string? authorizationHeader,
         [FromServices] PrincipalCredentialService credentials,
         [FromServices] SessionLeaseService sessions,
+        [FromServices] AbuseProtectionService abuseProtection,
         [FromServices] IWallClock clock,
         HttpContext httpContext,
         CancellationToken cancellationToken)
@@ -206,6 +273,21 @@ internal static class ContractEndpoints
             return AuthenticationRequired(httpContext);
         }
 
+        IPublisherPrincipal publisher = (IPublisherPrincipal)principal!;
+        if (!TryAcquireIdentity(
+                abuseProtection,
+                httpContext,
+                "DeleteSession",
+                Tenant(publisher.GameId, publisher.EnvironmentId),
+                publisher.Subject,
+                listingId.ToString(),
+                out AbuseProtectionService.AbuseLease? abuseLease))
+        {
+            return RateLimited(httpContext);
+        }
+
+        using (abuseLease)
+        {
             SessionServiceResult<bool> result = sessions.Delete(
                 principal!,
                 listingId,
@@ -213,6 +295,7 @@ internal static class ContractEndpoints
                 cancellationToken);
             return result.Succeeded ? Results.NoContent() : Error(result.Error);
         }
+    }
 
     private static IResult BrowseSessions(
         [FromQuery] int contractVersion,
@@ -224,6 +307,8 @@ internal static class ContractEndpoints
         [FromQuery] bool? excludeFull,
         [FromQuery] string? cursor,
         [FromServices] SessionBrowserService browser,
+        [FromServices] AbuseProtectionService abuseProtection,
+        HttpContext httpContext,
         CancellationToken cancellationToken)
     {
         if (!GameId.TryParse(gameId, out GameId parsedGameId)
@@ -233,6 +318,20 @@ internal static class ContractEndpoints
             return Error(RendezvousErrorCode.InvalidRequest);
         }
 
+        if (!TryAcquireIdentity(
+                abuseProtection,
+                httpContext,
+                "BrowseSessions",
+                Tenant(parsedGameId, parsedEnvironmentId),
+                null,
+                null,
+                out AbuseProtectionService.AbuseLease? abuseLease))
+        {
+            return RateLimited(httpContext);
+        }
+
+        using (abuseLease)
+        {
             BrowserServiceResult<BrowseSessionsResponse> result = browser.Browse(new()
             {
                 ContractVersion = contractVersion,
@@ -248,6 +347,7 @@ internal static class ContractEndpoints
                 ? Results.Ok(result.Value)
                 : Error(result.Error);
         }
+    }
 
     private static IResult GetSession(
         SessionListingId listingId,
@@ -256,6 +356,8 @@ internal static class ContractEndpoints
         [FromQuery] string environmentId,
         [FromQuery] uint protocolVersion,
         [FromServices] SessionBrowserService browser,
+        [FromServices] AbuseProtectionService abuseProtection,
+        HttpContext httpContext,
         CancellationToken cancellationToken)
     {
         if (ContractValidation.ValidateContractVersion(contractVersion) != RendezvousErrorCode.None)
@@ -269,6 +371,20 @@ internal static class ContractEndpoints
             return Error(RendezvousErrorCode.InvalidRequest);
         }
 
+        if (!TryAcquireIdentity(
+                abuseProtection,
+                httpContext,
+                "GetSession",
+                Tenant(parsedGameId, parsedEnvironmentId),
+                null,
+                listingId.ToString(),
+                out AbuseProtectionService.AbuseLease? abuseLease))
+        {
+            return RateLimited(httpContext);
+        }
+
+        using (abuseLease)
+        {
             BrowserServiceResult<GetSessionResponse> result = browser.Get(
                 listingId,
                 parsedGameId,
@@ -279,6 +395,7 @@ internal static class ContractEndpoints
                 ? Results.Ok(result.Value)
                 : Error(result.Error);
         }
+    }
 
     private static IResult BrowseHostJoinAttempts(
         SessionListingId listingId,
@@ -287,7 +404,23 @@ internal static class ContractEndpoints
         [FromQuery] int? pageSize,
         [FromQuery] string? cursor,
         [FromServices] JoinAttemptService attempts,
+        [FromServices] AbuseProtectionService abuseProtection,
+        HttpContext httpContext,
         CancellationToken cancellationToken)
+    {
+        if (!TryAcquireIdentity(
+                abuseProtection,
+                httpContext,
+                "BrowseHostJoinAttempts",
+                null,
+                AbuseProtectionService.FingerprintSecret(leaseToken ?? string.Empty),
+                listingId.ToString(),
+                out AbuseProtectionService.AbuseLease? abuseLease))
+        {
+            return RateLimited(httpContext);
+        }
+
+        using (abuseLease)
         {
             JoinAttemptServiceResult<BrowseHostJoinAttemptsResponse> result = attempts.BrowseForHost(
                 listingId,
@@ -300,10 +433,12 @@ internal static class ContractEndpoints
                 ? Results.Ok(result.Value)
                 : Error(result.Error);
         }
+    }
 
     private static IResult CreateJoinAttempt(
         [FromBody] CreateJoinAttemptRequest request,
         [FromServices] JoinAttemptService attempts,
+        [FromServices] AbuseProtectionService abuseProtection,
         HttpContext httpContext,
         CancellationToken cancellationToken)
     {
@@ -313,6 +448,20 @@ internal static class ContractEndpoints
         }
 
         string clientSubject = attempts.CreateAnonymousClientSubject(remoteAddress);
+        if (!TryAcquireIdentity(
+                abuseProtection,
+                httpContext,
+                "CreateJoinAttempt",
+                Tenant(request.GameId, request.EnvironmentId),
+                clientSubject,
+                request.ListingId.ToString(),
+                out AbuseProtectionService.AbuseLease? abuseLease))
+        {
+            return RateLimited(httpContext);
+        }
+
+        using (abuseLease)
+        {
             JoinAttemptServiceResult<CreateJoinAttemptResponse> result = attempts.Create(
                 clientSubject,
                 request,
@@ -321,12 +470,29 @@ internal static class ContractEndpoints
                 ? Results.Created($"/v1/join-attempts/{result.Value.AttemptId}", result.Value)
                 : Error(result.Error);
         }
+    }
 
     private static IResult CancelJoinAttempt(
         JoinAttemptId attemptId,
         [FromHeader(Name = "X-Rendezvous-Client-Punch-Capability")] string clientPunchCapability,
         [FromServices] JoinAttemptService attempts,
+        [FromServices] AbuseProtectionService abuseProtection,
+        HttpContext httpContext,
         CancellationToken cancellationToken)
+    {
+        if (!TryAcquireIdentity(
+                abuseProtection,
+                httpContext,
+                "CancelJoinAttempt",
+                null,
+                AbuseProtectionService.FingerprintSecret(clientPunchCapability ?? string.Empty),
+                attemptId.ToString(),
+                out AbuseProtectionService.AbuseLease? abuseLease))
+        {
+            return RateLimited(httpContext);
+        }
+
+        using (abuseLease)
         {
             JoinAttemptServiceResult<bool> result = attempts.Cancel(
                 attemptId,
@@ -334,13 +500,30 @@ internal static class ContractEndpoints
                 cancellationToken);
             return result.Succeeded ? Results.NoContent() : Error(result.Error);
         }
+    }
 
     private static IResult ReportConnectionOutcome(
         JoinAttemptId attemptId,
         [FromHeader(Name = "X-Rendezvous-Client-Punch-Capability")] string clientPunchCapability,
         [FromBody] ReportConnectionOutcomeRequest request,
         [FromServices] ConnectionOutcomeService outcomes,
+        [FromServices] AbuseProtectionService abuseProtection,
+        HttpContext httpContext,
         CancellationToken cancellationToken)
+    {
+        if (!TryAcquireIdentity(
+                abuseProtection,
+                httpContext,
+                "ReportConnectionOutcome",
+                null,
+                AbuseProtectionService.FingerprintSecret(clientPunchCapability ?? string.Empty),
+                attemptId.ToString(),
+                out AbuseProtectionService.AbuseLease? abuseLease))
+        {
+            return RateLimited(httpContext);
+        }
+
+        using (abuseLease)
         {
             ConnectionOutcomeServiceResult result = outcomes.Report(
                 attemptId,
@@ -351,6 +534,7 @@ internal static class ContractEndpoints
                 ? Results.Ok(result.Value)
                 : Error(result.Error);
         }
+    }
 
     private static bool TryAuthenticatePublisher(
         string? authorizationHeader,
@@ -377,11 +561,41 @@ internal static class ContractEndpoints
         return true;
     }
 
-    private static IResult Error(RendezvousErrorCode code) => Results.Json(
+    private static bool TryAcquireIdentity(
+        AbuseProtectionService abuseProtection,
+        HttpContext httpContext,
+        string operation,
+        string? tenant,
+        string? principal,
+        string? resource,
+        out AbuseProtectionService.AbuseLease? lease)
+    {
+        if (abuseProtection.TryAcquireHttpIdentity(
+                operation,
+                httpContext.Connection.RemoteIpAddress,
+                tenant,
+                principal,
+                resource,
+                out lease,
+                out int retryAfterSeconds))
+        {
+            return true;
+        }
+
+        httpContext.Response.Headers.RetryAfter = retryAfterSeconds.ToString(
+            System.Globalization.CultureInfo.InvariantCulture);
+        return false;
+    }
+
+    private static string Tenant(GameId gameId, EnvironmentId environmentId) =>
+        $"{gameId.Value}/{environmentId.Value}";
+
+    private static IResult Error(RendezvousErrorCode code, int? retryAfterSeconds = null) => Results.Json(
         new ApiError
         {
             Code = code,
             Message = ErrorMessage(code),
+            RetryAfterSeconds = retryAfterSeconds,
         },
         ContractJson.Options,
         statusCode: ErrorStatus(code));
@@ -392,6 +606,18 @@ internal static class ContractEndpoints
         return Error(RendezvousErrorCode.AuthenticationRequired);
     }
 
+    private static IResult RateLimited(HttpContext context)
+    {
+        int? retryAfterSeconds = int.TryParse(
+            context.Response.Headers.RetryAfter,
+            System.Globalization.NumberStyles.None,
+            System.Globalization.CultureInfo.InvariantCulture,
+            out int parsed)
+            ? Math.Clamp(parsed, 1, 60)
+            : null;
+        return Error(RendezvousErrorCode.RateLimited, retryAfterSeconds);
+    }
+
     private static int ErrorStatus(RendezvousErrorCode code) => code switch
     {
         RendezvousErrorCode.AuthenticationRequired => StatusCodes.Status401Unauthorized,
@@ -417,6 +643,7 @@ internal static class ContractEndpoints
         RendezvousErrorCode.Expired => "The session lease has expired.",
         RendezvousErrorCode.StaleHost => "The session has no fresh host presence.",
         RendezvousErrorCode.IncompatibleProtocol => "The gameplay protocol is not enabled for this game.",
+        RendezvousErrorCode.RateLimited => "The request rate limit was exceeded.",
         RendezvousErrorCode.CapacityExceeded => "The configured session capacity is currently exhausted.",
         RendezvousErrorCode.ServiceUnavailable => "Session state is temporarily unavailable.",
         RendezvousErrorCode.UnsupportedContractVersion => "The requested contract version is not supported.",

src/FinalFactory.Rendezvous.Server/Http/RendezvousExceptionHandler.cs

@@ -4,7 +4,8 @@ using Microsoft.AspNetCore.Diagnostics;
 
 namespace FinalFactory.Rendezvous.Server.Http;
 
-internal sealed class RendezvousExceptionHandler : IExceptionHandler
+internal sealed partial class RendezvousExceptionHandler(
+    ILogger<RendezvousExceptionHandler> logger) : IExceptionHandler
 {
     public async ValueTask<bool> TryHandleAsync(
         HttpContext httpContext,
@@ -17,16 +18,31 @@ internal sealed class RendezvousExceptionHandler : IExceptionHandler
         }
 
         bool invalidRequest = exception is BadHttpRequestException or JsonException;
-        httpContext.Response.StatusCode = invalidRequest
+        bool payloadTooLarge = exception is BadHttpRequestException
+        {
+            StatusCode: StatusCodes.Status413PayloadTooLarge,
+        };
+        httpContext.Response.StatusCode = payloadTooLarge
+            ? StatusCodes.Status413PayloadTooLarge
+            : invalidRequest
                 ? StatusCodes.Status400BadRequest
                 : StatusCodes.Status500InternalServerError;
+        LogRequestFailure(
+            logger,
+            payloadTooLarge ? "payload-too-large" : invalidRequest ? "invalid-request" : "internal-error",
+            httpContext.Response.StatusCode,
+            httpContext.Response.Headers["X-Rendezvous-Correlation-ID"].ToString() is { Length: > 0 } value
+                ? value
+                : "unavailable");
         await httpContext.Response.WriteAsJsonAsync(
             new ApiError
             {
                 Code = invalidRequest
                     ? RendezvousErrorCode.InvalidRequest
                     : RendezvousErrorCode.InternalError,
-                Message = invalidRequest
+                Message = payloadTooLarge
+                    ? "The request body exceeds the supported size."
+                    : invalidRequest
                         ? "The request body, route, or query value is invalid."
                         : "The service could not complete the request.",
             },
@@ -34,4 +50,14 @@ internal sealed class RendezvousExceptionHandler : IExceptionHandler
             cancellationToken).ConfigureAwait(false);
         return true;
     }
+
+    [LoggerMessage(
+        EventId = 200,
+        Level = LogLevel.Warning,
+        Message = "Request failed with {FailureKind} and HTTP status {StatusCode}; correlation {CorrelationId}")]
+    private static partial void LogRequestFailure(
+        ILogger logger,
+        string failureKind,
+        int statusCode,
+        string correlationId);
 }

src/FinalFactory.Rendezvous.Server/Observability/AuditOptions.cs

@@ -0,0 +1,14 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace FinalFactory.Rendezvous.Server.Observability;
+
+internal sealed class AuditOptions
+{
+    public const string SectionName = "Rendezvous:Audit";
+
+    [Range(100, 100_000)]
+    public int MaxEntries { get; set; } = 10_000;
+
+    [Range(1, 30)]
+    public int RetentionDays { get; set; } = 30;
+}

src/FinalFactory.Rendezvous.Server/Observability/AuditTrail.cs

@@ -0,0 +1,134 @@
+using System.Security.Cryptography;
+using System.Text;
+using Microsoft.Extensions.Options;
+
+namespace FinalFactory.Rendezvous.Server.Observability;
+
+internal sealed partial class AuditTrail
+{
+    private readonly object _gate = new();
+    private readonly LinkedList<AuditEntry> _entries = [];
+    private readonly AuditOptions _options;
+    private readonly TimeProvider _timeProvider;
+    private readonly ILogger<AuditTrail> _logger;
+    private readonly RendezvousTelemetry _telemetry;
+
+    public AuditTrail(
+        IOptions<AuditOptions> options,
+        ILogger<AuditTrail> logger,
+        RendezvousTelemetry telemetry,
+        TimeProvider? timeProvider = null)
+    {
+        _options = options.Value;
+        _logger = logger;
+        _telemetry = telemetry;
+        _timeProvider = timeProvider ?? TimeProvider.System;
+    }
+
+    public void Record(
+        string actorSubject,
+        string action,
+        string result,
+        string targetKind,
+        string targetIdentifier,
+        string correlationId)
+    {
+        DateTimeOffset now = _timeProvider.GetUtcNow();
+        AuditEntry entry = new(
+            now,
+            Fingerprint(actorSubject),
+            action,
+            result,
+            targetKind,
+            Fingerprint(targetIdentifier),
+            correlationId);
+        lock (_gate)
+        {
+            PurgeExpired(now);
+
+            while (_entries.Count >= _options.MaxEntries)
+            {
+                _entries.RemoveFirst();
+            }
+
+            _entries.AddLast(entry);
+        }
+
+        _telemetry.RecordAudit(action, result);
+        LogOperatorAction(
+            _logger,
+            entry.Timestamp,
+            entry.ActorFingerprint,
+            action,
+            result,
+            targetKind,
+            entry.TargetFingerprint,
+            correlationId);
+    }
+
+    public IReadOnlyDictionary<string, long> GetAggregateCounts()
+    {
+        lock (_gate)
+        {
+            PurgeExpired(_timeProvider.GetUtcNow());
+            return _entries
+                .GroupBy(static entry => $"{entry.Action}:{entry.Result}", StringComparer.Ordinal)
+                .ToDictionary(
+                    static group => group.Key,
+                    static group => (long)group.Count(),
+                    StringComparer.Ordinal);
+        }
+    }
+
+    internal IReadOnlyList<AuditEntry> GetEntriesForTests()
+    {
+        lock (_gate)
+        {
+            PurgeExpired(_timeProvider.GetUtcNow());
+            return _entries.ToArray();
+        }
+    }
+
+    private void PurgeExpired(DateTimeOffset now)
+    {
+        DateTimeOffset oldest = now.AddDays(-_options.RetentionDays);
+        while (_entries.First is { Value.Timestamp: var timestamp }
+               && timestamp < oldest)
+        {
+            _entries.RemoveFirst();
+        }
+    }
+
+    private static string Fingerprint(string value)
+    {
+        byte[] digest = SHA256.HashData(Encoding.UTF8.GetBytes(value));
+        return Convert.ToHexString(digest.AsSpan(0, 12));
+    }
+
+    [LoggerMessage(
+        EventId = 100,
+        Level = LogLevel.Information,
+        Message = "Operator audit at {Timestamp}: actor {ActorFingerprint} action {Action} completed with {Result} for {TargetKind} target {TargetFingerprint}; correlation {CorrelationId}")]
+    private static partial void LogOperatorAction(
+        ILogger logger,
+        DateTimeOffset timestamp,
+        string actorFingerprint,
+        string action,
+        string result,
+        string targetKind,
+        string targetFingerprint,
+        string correlationId);
+}
+
+internal sealed record AuditEntry(
+    DateTimeOffset Timestamp,
+    string ActorFingerprint,
+    string Action,
+    string Result,
+    string TargetKind,
+    string TargetFingerprint,
+    string CorrelationId)
+{
+    public override string ToString() =>
+        $"[AuditEntry {Action}/{Result}; actor and target fingerprinted]";
+}

src/FinalFactory.Rendezvous.Server/Observability/HealthEndpoints.cs

@@ -0,0 +1,30 @@
+using FinalFactory.Rendezvous.Contracts;
+
+namespace FinalFactory.Rendezvous.Server.Observability;
+
+internal static class HealthEndpoints
+{
+    public static IEndpointRouteBuilder MapRendezvousHealthEndpoints(
+        this IEndpointRouteBuilder endpoints)
+    {
+        endpoints.MapGet(
+                "/health/live",
+                static () => Results.Ok(new HealthResponse { Status = "live" }))
+            .Produces<HealthResponse>()
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
+            .WithName("GetLiveness")
+            .WithTags("Health");
+        endpoints.MapGet(
+                "/health/ready",
+                static (RendezvousReadiness readiness) =>
+                    !readiness.GetSnapshot().IsReady
+                        ? Results.StatusCode(StatusCodes.Status503ServiceUnavailable)
+                        : Results.Ok(new HealthResponse { Status = "ready" }))
+            .Produces<HealthResponse>()
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
+            .Produces(StatusCodes.Status503ServiceUnavailable)
+            .WithName("GetReadiness")
+            .WithTags("Health");
+        return endpoints;
+    }
+}

src/FinalFactory.Rendezvous.Server/Observability/RendezvousReadiness.cs

@@ -0,0 +1,41 @@
+using FinalFactory.Rendezvous.Server.Provisioning;
+using FinalFactory.Rendezvous.Server.State;
+using FinalFactory.Rendezvous.Server.Transport;
+using Microsoft.Extensions.Options;
+
+namespace FinalFactory.Rendezvous.Server.Observability;
+
+internal sealed class RendezvousReadiness(
+    UdpMediatorService mediator,
+    ProvisioningReadiness provisioning,
+    IEphemeralRendezvousStore state,
+    IOptions<UdpMediatorOptions> udpOptions)
+{
+    public ReadinessSnapshot GetSnapshot()
+    {
+        bool ipv6Required = !string.IsNullOrWhiteSpace(udpOptions.Value.Ipv6ListenAddress);
+        return new ReadinessSnapshot(
+            HttpListenerReady: true,
+            UdpIpv4ListenerReady: mediator.LocalEndpoint is not null,
+            UdpIpv6ListenerReady: !ipv6Required || mediator.LocalIpv6Endpoint is not null,
+            ProvisioningReady: provisioning.IsReady,
+            StoreAvailable: state.IsAvailable,
+            Draining: state.IsDraining);
+    }
+}
+
+internal sealed record ReadinessSnapshot(
+    bool HttpListenerReady,
+    bool UdpIpv4ListenerReady,
+    bool UdpIpv6ListenerReady,
+    bool ProvisioningReady,
+    bool StoreAvailable,
+    bool Draining)
+{
+    public bool IsReady => HttpListenerReady
+        && UdpIpv4ListenerReady
+        && UdpIpv6ListenerReady
+        && ProvisioningReady
+        && StoreAvailable
+        && !Draining;
+}

src/FinalFactory.Rendezvous.Server/Observability/RendezvousTelemetry.cs

@@ -0,0 +1,126 @@
+using System.Diagnostics;
+using System.Diagnostics.Metrics;
+using FinalFactory.Rendezvous.Server.State;
+
+namespace FinalFactory.Rendezvous.Server.Observability;
+
+internal sealed class RendezvousTelemetry : IDisposable
+{
+    public const string MeterName = "FinalFactory.Rendezvous";
+    public const string ActivitySourceName = "FinalFactory.Rendezvous.Server";
+
+    private readonly InMemoryEphemeralRendezvousStore _store;
+    private readonly Meter _meter = new(MeterName, "1.0.0");
+    private readonly ActivitySource _activities = new(ActivitySourceName, "1.0.0");
+    private readonly Counter<long> _httpRequests;
+    private readonly Histogram<double> _httpDuration;
+    private readonly Counter<long> _udpResults;
+    private readonly Histogram<double> _udpDuration;
+    private readonly Counter<long> _limiterDrops;
+    private readonly Counter<long> _auditEvents;
+    private readonly Counter<long> _connectionOutcomes;
+    private readonly Counter<long> _operatorAuthentication;
+    private readonly Histogram<double> _pairingLatency;
+
+    public RendezvousTelemetry(InMemoryEphemeralRendezvousStore store)
+    {
+        _store = store;
+        _httpRequests = _meter.CreateCounter<long>("rendezvous.http.requests");
+        _httpDuration = _meter.CreateHistogram<double>(
+            "rendezvous.http.duration",
+            "ms");
+        _udpResults = _meter.CreateCounter<long>("rendezvous.udp.results");
+        _udpDuration = _meter.CreateHistogram<double>(
+            "rendezvous.udp.duration",
+            "ms");
+        _limiterDrops = _meter.CreateCounter<long>("rendezvous.limiter.drops");
+        _auditEvents = _meter.CreateCounter<long>("rendezvous.audit.events");
+        _connectionOutcomes = _meter.CreateCounter<long>("rendezvous.connection.outcomes");
+        _operatorAuthentication = _meter.CreateCounter<long>("rendezvous.operator.authentication");
+        _pairingLatency = _meter.CreateHistogram<double>(
+            "rendezvous.pairing.latency",
+            "ms");
+        _meter.CreateObservableGauge(
+            "rendezvous.store.active_listings",
+            () => _store.GetMetricsSnapshot().ActiveListings);
+        _meter.CreateObservableGauge(
+            "rendezvous.store.active_leases",
+            () => _store.GetMetricsSnapshot().ActiveListings);
+        _meter.CreateObservableGauge(
+            "rendezvous.store.active_attempts",
+            () => _store.GetMetricsSnapshot().ActiveJoinAttempts);
+        _meter.CreateObservableGauge(
+            "rendezvous.queue.depth",
+            () => _store.GetMetricsSnapshot().ActiveJoinAttempts);
+        _meter.CreateObservableGauge(
+            "rendezvous.store.replay_markers",
+            () => _store.GetMetricsSnapshot().ReplayMarkers);
+        _meter.CreateObservableGauge(
+            "rendezvous.store.available",
+            () => _store.GetMetricsSnapshot().IsAvailable ? 1 : 0);
+        _meter.CreateObservableCounter(
+            "rendezvous.store.expiry_churn",
+            () => _store.GetMetricsSnapshot().ExpiryChurn);
+    }
+
+    public Activity? StartActivity(string name, ActivityKind kind = ActivityKind.Internal) =>
+        _activities.StartActivity(name, kind);
+
+    public void RecordHttp(string operation, int statusCode, double elapsedMilliseconds)
+    {
+        TagList tags = new()
+        {
+            { "operation", operation },
+            { "status_code", statusCode },
+        };
+        _httpRequests.Add(1, tags);
+        _httpDuration.Record(elapsedMilliseconds, tags);
+    }
+
+    public void RecordUdp(string operation, string result, double elapsedMilliseconds)
+    {
+        TagList tags = new()
+        {
+            { "operation", operation },
+            { "result", result },
+        };
+        _udpResults.Add(1, tags);
+        _udpDuration.Record(elapsedMilliseconds, tags);
+    }
+
+    public void RecordLimiterDrop(string transport, string partition) =>
+        _limiterDrops.Add(1, new TagList
+        {
+            { "transport", transport },
+            { "partition", partition },
+        });
+
+    public void RecordAudit(string action, string result) =>
+        _auditEvents.Add(1, new TagList
+        {
+            { "action", action },
+            { "result", result },
+        });
+
+    public void RecordConnectionOutcome(string outcome, string elapsedBucket) =>
+        _connectionOutcomes.Add(1, new TagList
+        {
+            { "outcome", outcome },
+            { "elapsed_bucket", elapsedBucket },
+        });
+
+    public void RecordOperatorAuthentication(string result) =>
+        _operatorAuthentication.Add(1, new TagList
+        {
+            { "result", result },
+        });
+
+    public void RecordPairingLatency(double elapsedMilliseconds) =>
+        _pairingLatency.Record(elapsedMilliseconds);
+
+    public void Dispose()
+    {
+        _activities.Dispose();
+        _meter.Dispose();
+    }
+}

src/FinalFactory.Rendezvous.Server/Observability/TelemetryMiddleware.cs

@@ -0,0 +1,32 @@
+using System.Diagnostics;
+
+namespace FinalFactory.Rendezvous.Server.Observability;
+
+internal sealed class TelemetryMiddleware(
+    RequestDelegate next,
+    RendezvousTelemetry telemetry)
+{
+    public async Task InvokeAsync(HttpContext context)
+    {
+        string operation = context.GetEndpoint()?.Metadata.GetMetadata<IEndpointNameMetadata>()
+            ?.EndpointName ?? "Unmatched";
+        long started = Stopwatch.GetTimestamp();
+        using Activity? activity = telemetry.StartActivity(
+            $"HTTP {operation}",
+            ActivityKind.Server);
+        string correlationId = activity?.TraceId.ToString() ?? Guid.NewGuid().ToString("N");
+        context.Response.Headers["X-Rendezvous-Correlation-ID"] = correlationId;
+        activity?.SetTag("rendezvous.operation", operation);
+        try
+        {
+            await next(context).ConfigureAwait(false);
+        }
+        finally
+        {
+            telemetry.RecordHttp(
+                operation,
+                context.Response.StatusCode,
+                Stopwatch.GetElapsedTime(started).TotalMilliseconds);
+        }
+    }
+}

src/FinalFactory.Rendezvous.Server/Operations/OperatorEndpoints.cs

@@ -0,0 +1,428 @@
+using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Observability;
+using FinalFactory.Rendezvous.Server.Provisioning;
+using FinalFactory.Rendezvous.Server.State;
+using Microsoft.AspNetCore.Mvc;
+
+namespace FinalFactory.Rendezvous.Server.Operations;
+
+internal static class OperatorEndpoints
+{
+    private const string CorrelationHeader = "X-Rendezvous-Correlation-ID";
+
+    public static IEndpointRouteBuilder MapOperatorEndpoints(this IEndpointRouteBuilder endpoints)
+    {
+        RouteGroupBuilder group = endpoints.MapGroup("/v1/operator").WithTags("Operator");
+        group.MapGet("/status", GetStatus)
+            .Produces<OperatorStatusResponse>()
+            .Produces<ApiError>(StatusCodes.Status401Unauthorized)
+            .Produces<ApiError>(StatusCodes.Status403Forbidden)
+            .Produces<ApiError>(StatusCodes.Status404NotFound)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
+            .WithName("GetOperatorStatus");
+        group.MapPost("/listings/revoke", RevokeListing)
+            .Accepts<RevokeListingRequest>("application/json")
+            .Produces<OperatorActionResponse>()
+            .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status413PayloadTooLarge)
+            .Produces<ApiError>(StatusCodes.Status401Unauthorized)
+            .Produces<ApiError>(StatusCodes.Status403Forbidden)
+            .Produces<ApiError>(StatusCodes.Status404NotFound)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
+            .Produces<ApiError>(StatusCodes.Status503ServiceUnavailable)
+            .WithName("RevokeOperatorListing");
+        group.MapPost("/principals/revoke", RevokePrincipal)
+            .Accepts<RevokePrincipalRequest>("application/json")
+            .Produces<OperatorActionResponse>()
+            .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status413PayloadTooLarge)
+            .Produces<ApiError>(StatusCodes.Status401Unauthorized)
+            .Produces<ApiError>(StatusCodes.Status403Forbidden)
+            .Produces<ApiError>(StatusCodes.Status404NotFound)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
+            .Produces<ApiError>(StatusCodes.Status503ServiceUnavailable)
+            .WithName("RevokeOperatorPrincipal");
+        group.MapPost("/keys/revoke", RevokeSigningKey)
+            .Accepts<RevokeSigningKeyRequest>("application/json")
+            .Produces<OperatorActionResponse>()
+            .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status413PayloadTooLarge)
+            .Produces<ApiError>(StatusCodes.Status401Unauthorized)
+            .Produces<ApiError>(StatusCodes.Status403Forbidden)
+            .Produces<ApiError>(StatusCodes.Status404NotFound)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
+            .WithName("RevokeOperatorSigningKey");
+        group.MapPost("/drain", BeginDrain)
+            .Accepts<BeginDrainRequest>("application/json")
+            .Produces<OperatorActionResponse>()
+            .Produces<ApiError>(StatusCodes.Status400BadRequest)
+            .Produces<ApiError>(StatusCodes.Status413PayloadTooLarge)
+            .Produces<ApiError>(StatusCodes.Status401Unauthorized)
+            .Produces<ApiError>(StatusCodes.Status403Forbidden)
+            .Produces<ApiError>(StatusCodes.Status404NotFound)
+            .Produces<ApiError>(StatusCodes.Status429TooManyRequests)
+            .WithName("BeginOperatorDrain");
+        return endpoints;
+    }
+
+    private static IResult GetStatus(
+        [FromHeader(Name = "Authorization")] string? authorization,
+        [FromServices] PrincipalCredentialService credentials,
+        [FromServices] IWallClock clock,
+        [FromServices] OperatorService service,
+        [FromServices] AuditTrail audit,
+        [FromServices] RendezvousTelemetry telemetry,
+        HttpContext context)
+    {
+        if (!TryAuthorize(
+                authorization,
+                OperatorPermission.ReadPolicy,
+                "inspect-status",
+                credentials,
+                clock,
+                audit,
+                telemetry,
+                context,
+                out OperatorPrincipal? principal,
+                out IResult? failure))
+        {
+            return failure!;
+        }
+
+        OperatorStatusResponse response = service.GetStatus();
+        audit.Record(
+            principal!.Subject,
+            "inspect-status",
+            "succeeded",
+            "service",
+            "rendezvous",
+            Correlation(context));
+        return Results.Ok(response);
+    }
+
+    private static IResult RevokeListing(
+        [FromBody] RevokeListingRequest request,
+        [FromHeader(Name = "Authorization")] string? authorization,
+        [FromServices] PrincipalCredentialService credentials,
+        [FromServices] IWallClock clock,
+        [FromServices] OperatorService service,
+        [FromServices] AuditTrail audit,
+        [FromServices] RendezvousTelemetry telemetry,
+        HttpContext context,
+        CancellationToken cancellationToken)
+    {
+        if (!TryAuthorize(
+                authorization,
+                OperatorPermission.RevokePublisher,
+                "revoke-listing",
+                credentials,
+                clock,
+                audit,
+                telemetry,
+                context,
+                out OperatorPrincipal? principal,
+                out IResult? failure))
+        {
+            return failure!;
+        }
+
+        bool valid = SessionListingId.TryParse(request.ListingId, out SessionListingId listingId);
+        if (!valid || !string.Equals(request.ListingId, request.ConfirmListingId, StringComparison.Ordinal))
+        {
+            AuditRejected(audit, principal!, "revoke-listing", "listing", request.ListingId, context);
+            return BadRequest("A valid listing ID and an exact repeated confirmation are required.");
+        }
+
+        StoreResult<bool> result = service.RevokeListing(listingId, cancellationToken);
+        return StoreActionResult(
+            result.Code,
+            audit,
+            principal!,
+            "revoke-listing",
+            "listing",
+            request.ListingId,
+            context,
+            affectedResources: result.Succeeded ? 1 : null);
+    }
+
+    private static IResult RevokePrincipal(
+        [FromBody] RevokePrincipalRequest request,
+        [FromHeader(Name = "Authorization")] string? authorization,
+        [FromServices] PrincipalCredentialService credentials,
+        [FromServices] IWallClock clock,
+        [FromServices] OperatorService service,
+        [FromServices] AuditTrail audit,
+        [FromServices] RendezvousTelemetry telemetry,
+        HttpContext context,
+        CancellationToken cancellationToken)
+    {
+        if (!TryAuthorize(
+                authorization,
+                OperatorPermission.RevokePublisher,
+                "revoke-principal",
+                credentials,
+                clock,
+                audit,
+                telemetry,
+                context,
+                out OperatorPrincipal? principal,
+                out IResult? failure))
+        {
+            return failure!;
+        }
+
+        bool safeSubject = request.Subject is { Length: > 0 and <= 128 }
+            && request.Subject.All(static character => character is >= '!' and <= '~');
+        if (!safeSubject
+            || !string.Equals(request.Subject, request.ConfirmSubject, StringComparison.Ordinal)
+            || request.LifetimeSeconds is < 1 or > 600)
+        {
+            AuditRejected(audit, principal!, "revoke-principal", "principal", request.Subject, context);
+            return BadRequest("A valid subject, exact repeated confirmation, and 1-600 second lifetime are required.");
+        }
+
+        StoreResult<int> result = service.RevokePrincipal(
+            request.Subject,
+            TimeSpan.FromSeconds(request.LifetimeSeconds),
+            cancellationToken);
+        return StoreActionResult(
+            result.Code,
+            audit,
+            principal!,
+            "revoke-principal",
+            "principal",
+            request.Subject,
+            context,
+            result.Value);
+    }
+
+    private static IResult RevokeSigningKey(
+        [FromBody] RevokeSigningKeyRequest request,
+        [FromHeader(Name = "Authorization")] string? authorization,
+        [FromServices] PrincipalCredentialService credentials,
+        [FromServices] IWallClock clock,
+        [FromServices] OperatorService service,
+        [FromServices] AuditTrail audit,
+        [FromServices] RendezvousTelemetry telemetry,
+        HttpContext context)
+    {
+        if (!TryAuthorize(
+                authorization,
+                OperatorPermission.RotateKeys,
+                "revoke-signing-key",
+                credentials,
+                clock,
+                audit,
+                telemetry,
+                context,
+                out OperatorPrincipal? principal,
+                out IResult? failure))
+        {
+            return failure!;
+        }
+
+        bool safeKeyId = request.KeyId is { Length: > 0 and <= 64 }
+            && request.KeyId.All(static character => character is
+                >= 'A' and <= 'Z'
+                or >= 'a' and <= 'z'
+                or >= '0' and <= '9'
+                or '-'
+                or '_');
+        if (!safeKeyId || !string.Equals(request.KeyId, request.ConfirmKeyId, StringComparison.Ordinal))
+        {
+            AuditRejected(audit, principal!, "revoke-signing-key", "signing-key", request.KeyId, context);
+            return BadRequest("A valid key ID and an exact repeated confirmation are required.");
+        }
+
+        bool revoked = service.RevokeSigningKey(request.KeyId);
+        string result = revoked ? "succeeded" : "not-found";
+        audit.Record(
+            principal!.Subject,
+            "revoke-signing-key",
+            result,
+            "signing-key",
+            request.KeyId,
+            Correlation(context));
+        return revoked
+            ? Results.Ok(new OperatorActionResponse { Status = "completed" })
+            : Error(RendezvousErrorCode.NotFound, "The requested resource was not found.");
+    }
+
+    private static IResult BeginDrain(
+        [FromBody] BeginDrainRequest request,
+        [FromHeader(Name = "Authorization")] string? authorization,
+        [FromServices] PrincipalCredentialService credentials,
+        [FromServices] IWallClock clock,
+        [FromServices] OperatorService service,
+        [FromServices] AuditTrail audit,
+        [FromServices] RendezvousTelemetry telemetry,
+        HttpContext context,
+        CancellationToken cancellationToken)
+    {
+        if (!TryAuthorize(
+                authorization,
+                OperatorPermission.ManagePolicy,
+                "begin-drain",
+                credentials,
+                clock,
+                audit,
+                telemetry,
+                context,
+                out OperatorPrincipal? principal,
+                out IResult? failure))
+        {
+            return failure!;
+        }
+
+        if (!string.Equals(request.Confirmation, "DRAIN", StringComparison.Ordinal))
+        {
+            AuditRejected(audit, principal!, "begin-drain", "service", "rendezvous", context);
+            return BadRequest("The confirmation value must be exactly 'DRAIN'.");
+        }
+
+        service.BeginDrain(cancellationToken);
+        audit.Record(
+            principal!.Subject,
+            "begin-drain",
+            "succeeded",
+            "service",
+            "rendezvous",
+            Correlation(context));
+        return Results.Ok(new OperatorActionResponse { Status = "draining" });
+    }
+
+    private static bool TryAuthorize(
+        string? authorization,
+        OperatorPermission requiredPermission,
+        string operation,
+        PrincipalCredentialService credentials,
+        IWallClock clock,
+        AuditTrail audit,
+        RendezvousTelemetry telemetry,
+        HttpContext context,
+        out OperatorPrincipal? principal,
+        out IResult? failure)
+    {
+        principal = null;
+        failure = null;
+        const string prefix = "Bearer ";
+        if (authorization is null
+            || !authorization.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
+        {
+            telemetry.RecordOperatorAuthentication("rejected");
+            failure = AuthenticationRequired(context);
+            return false;
+        }
+
+        CredentialValidationResult validation = credentials.Validate(
+            authorization[prefix.Length..],
+            clock.UtcNow);
+        if (!validation.IsValid || validation.Principal is not OperatorPrincipal candidate)
+        {
+            telemetry.RecordOperatorAuthentication("rejected");
+            failure = AuthenticationRequired(context);
+            return false;
+        }
+
+        if (!candidate.Permissions.Contains(requiredPermission))
+        {
+            telemetry.RecordOperatorAuthentication("forbidden");
+            audit.Record(
+                candidate.Subject,
+                operation,
+                "forbidden",
+                "operator-operation",
+                operation,
+                Correlation(context));
+            failure = Error(RendezvousErrorCode.Forbidden, "The operator is not authorized for this operation.");
+            return false;
+        }
+
+        telemetry.RecordOperatorAuthentication("accepted");
+        principal = candidate;
+        return true;
+    }
+
+    private static IResult StoreActionResult(
+        StoreResultCode code,
+        AuditTrail audit,
+        OperatorPrincipal principal,
+        string action,
+        string targetKind,
+        string targetIdentifier,
+        HttpContext context,
+        int? affectedResources)
+    {
+        string auditResult = code == StoreResultCode.Success
+            ? "succeeded"
+            : code.ToString().ToLowerInvariant();
+        audit.Record(
+            principal.Subject,
+            action,
+            auditResult,
+            targetKind,
+            targetIdentifier,
+            Correlation(context));
+        return code switch
+        {
+            StoreResultCode.Success => Results.Ok(new OperatorActionResponse
+            {
+                Status = "completed",
+                AffectedResources = affectedResources,
+            }),
+            StoreResultCode.NotFound => Error(
+                RendezvousErrorCode.NotFound,
+                "The requested resource was not found."),
+            StoreResultCode.CapacityExceeded => Error(
+                RendezvousErrorCode.CapacityExceeded,
+                "The operation could not be retained within the configured capacity."),
+            StoreResultCode.ServiceUnavailable or StoreResultCode.Draining => Error(
+                RendezvousErrorCode.ServiceUnavailable,
+                "The service is not available for this operation."),
+            _ => Error(RendezvousErrorCode.Conflict, "The operation could not be completed."),
+        };
+    }
+
+    private static void AuditRejected(
+        AuditTrail audit,
+        OperatorPrincipal principal,
+        string action,
+        string targetKind,
+        string? targetIdentifier,
+        HttpContext context) => audit.Record(
+            principal.Subject,
+            action,
+            "rejected",
+            targetKind,
+            targetIdentifier ?? string.Empty,
+            Correlation(context));
+
+    private static string Correlation(HttpContext context) =>
+        context.Response.Headers[CorrelationHeader].ToString() is { Length: > 0 } value
+            ? value
+            : "unavailable";
+
+    private static IResult AuthenticationRequired(HttpContext context)
+    {
+        context.Response.Headers.WWWAuthenticate = "Bearer realm=\"operator\"";
+        return Error(
+            RendezvousErrorCode.AuthenticationRequired,
+            "A valid operator bearer credential is required.");
+    }
+
+    private static IResult BadRequest(string message) => Error(RendezvousErrorCode.InvalidRequest, message);
+
+    private static IResult Error(RendezvousErrorCode code, string message) => Results.Json(
+        new ApiError { Code = code, Message = message },
+        ContractJson.Options,
+        statusCode: code switch
+        {
+            RendezvousErrorCode.AuthenticationRequired => StatusCodes.Status401Unauthorized,
+            RendezvousErrorCode.Forbidden => StatusCodes.Status403Forbidden,
+            RendezvousErrorCode.NotFound => StatusCodes.Status404NotFound,
+            RendezvousErrorCode.CapacityExceeded => StatusCodes.Status429TooManyRequests,
+            RendezvousErrorCode.ServiceUnavailable => StatusCodes.Status503ServiceUnavailable,
+            RendezvousErrorCode.Conflict => StatusCodes.Status409Conflict,
+            _ => StatusCodes.Status400BadRequest,
+        });
+}

src/FinalFactory.Rendezvous.Server/Operations/OperatorModels.cs

@@ -0,0 +1,82 @@
+namespace FinalFactory.Rendezvous.Server.Operations;
+
+internal sealed record OperatorStatusResponse
+{
+    public required string Status { get; init; }
+    public required OperatorReadinessResponse Readiness { get; init; }
+    public required OperatorStoreResponse Store { get; init; }
+    public required IReadOnlyList<OperatorTenantResponse> Tenants { get; init; }
+    public required IReadOnlyList<OperatorSigningKeyResponse> SigningKeys { get; init; }
+    public required IReadOnlyDictionary<string, long> AuditCounts { get; init; }
+}
+
+internal sealed record OperatorReadinessResponse
+{
+    public required bool HttpListener { get; init; }
+    public required bool UdpIpv4Listener { get; init; }
+    public required bool UdpIpv6Listener { get; init; }
+    public required bool Provisioning { get; init; }
+    public required bool Store { get; init; }
+    public required bool Draining { get; init; }
+}
+
+internal sealed record OperatorStoreResponse
+{
+    public required int ActiveListings { get; init; }
+    public required int FreshPresenceBindings { get; init; }
+    public required int ActiveJoinAttempts { get; init; }
+    public required int RetainedOutcomeReports { get; init; }
+    public required int ReplayMarkers { get; init; }
+    public required int PrincipalRevocations { get; init; }
+    public required int IdempotencyEntries { get; init; }
+    public required long MaintenanceSweeps { get; init; }
+    public required long ExpiryChurn { get; init; }
+}
+
+internal sealed record OperatorTenantResponse
+{
+    public required string GameId { get; init; }
+    public required string EnvironmentId { get; init; }
+    public required string Status { get; init; }
+}
+
+internal sealed record OperatorSigningKeyResponse
+{
+    public required string KeyId { get; init; }
+    public required string Status { get; init; }
+    public required DateTimeOffset SignUntil { get; init; }
+    public required DateTimeOffset VerifyUntil { get; init; }
+    public string? GameId { get; init; }
+    public string? EnvironmentId { get; init; }
+    public required IReadOnlyList<string> CredentialKinds { get; init; }
+}
+
+internal sealed record OperatorActionResponse
+{
+    public required string Status { get; init; }
+    public int? AffectedResources { get; init; }
+}
+
+internal sealed record RevokeListingRequest
+{
+    public required string ListingId { get; init; }
+    public required string ConfirmListingId { get; init; }
+}
+
+internal sealed record RevokePrincipalRequest
+{
+    public required string Subject { get; init; }
+    public required string ConfirmSubject { get; init; }
+    public required int LifetimeSeconds { get; init; }
+}
+
+internal sealed record RevokeSigningKeyRequest
+{
+    public required string KeyId { get; init; }
+    public required string ConfirmKeyId { get; init; }
+}
+
+internal sealed record BeginDrainRequest
+{
+    public required string Confirmation { get; init; }
+}

src/FinalFactory.Rendezvous.Server/Operations/OperatorService.cs

@@ -0,0 +1,81 @@
+using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Observability;
+using FinalFactory.Rendezvous.Server.Provisioning;
+using FinalFactory.Rendezvous.Server.State;
+
+namespace FinalFactory.Rendezvous.Server.Operations;
+
+internal sealed class OperatorService(
+    InMemoryEphemeralRendezvousStore store,
+    ProvisioningRuntime provisioning,
+    RendezvousReadiness readiness,
+    AuditTrail audit,
+    IWallClock clock)
+{
+    public OperatorStatusResponse GetStatus()
+    {
+        ReadinessSnapshot readinessSnapshot = readiness.GetSnapshot();
+        EphemeralStoreSnapshot storeSnapshot = store.GetSnapshot();
+        return new OperatorStatusResponse
+        {
+            Status = readinessSnapshot.IsReady ? "ready" : "not-ready",
+            Readiness = new OperatorReadinessResponse
+            {
+                HttpListener = readinessSnapshot.HttpListenerReady,
+                UdpIpv4Listener = readinessSnapshot.UdpIpv4ListenerReady,
+                UdpIpv6Listener = readinessSnapshot.UdpIpv6ListenerReady,
+                Provisioning = readinessSnapshot.ProvisioningReady,
+                Store = readinessSnapshot.StoreAvailable,
+                Draining = readinessSnapshot.Draining,
+            },
+            Store = new OperatorStoreResponse
+            {
+                ActiveListings = storeSnapshot.ActiveListings,
+                FreshPresenceBindings = storeSnapshot.FreshPresenceBindings,
+                ActiveJoinAttempts = storeSnapshot.ActiveJoinAttempts,
+                RetainedOutcomeReports = storeSnapshot.RetainedOutcomeReports,
+                ReplayMarkers = storeSnapshot.ReplayMarkers,
+                PrincipalRevocations = storeSnapshot.PrincipalRevocations,
+                IdempotencyEntries = storeSnapshot.IdempotencyEntries,
+                MaintenanceSweeps = storeSnapshot.MaintenanceSweeps,
+                ExpiryChurn = storeSnapshot.ExpiryChurn,
+            },
+            Tenants = provisioning.Policies.EnabledPolicies
+                .OrderBy(static policy => policy.GameId.Value, StringComparer.Ordinal)
+                .ThenBy(static policy => policy.EnvironmentId.Value, StringComparer.Ordinal)
+                .Select(static policy => new OperatorTenantResponse
+                {
+                    GameId = policy.GameId.Value,
+                    EnvironmentId = policy.EnvironmentId.Value,
+                    Status = "enabled",
+                })
+                .ToArray(),
+            SigningKeys = provisioning.SigningKeys.GetStatuses(clock.UtcNow)
+                .Select(static key => new OperatorSigningKeyResponse
+                {
+                    KeyId = key.KeyId,
+                    Status = key.Status,
+                    SignUntil = key.SignUntil,
+                    VerifyUntil = key.VerifyUntil,
+                    GameId = key.GameId,
+                    EnvironmentId = key.EnvironmentId,
+                    CredentialKinds = key.CredentialKinds,
+                })
+                .ToArray(),
+            AuditCounts = audit.GetAggregateCounts(),
+        };
+    }
+
+    public StoreResult<bool> RevokeListing(
+        SessionListingId listingId,
+        CancellationToken cancellationToken) => store.RevokeListing(listingId, cancellationToken);
+
+    public StoreResult<int> RevokePrincipal(
+        string subject,
+        TimeSpan lifetime,
+        CancellationToken cancellationToken) => store.RevokePrincipal(subject, lifetime, cancellationToken);
+
+    public bool RevokeSigningKey(string keyId) => provisioning.SigningKeys.Revoke(keyId);
+
+    public void BeginDrain(CancellationToken cancellationToken) => store.BeginDrain(cancellationToken);
+}

src/FinalFactory.Rendezvous.Server/Program.cs

@@ -1,16 +1,24 @@
 using System.Net;
 using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Abuse;
 using FinalFactory.Rendezvous.Server.Browser;
 using FinalFactory.Rendezvous.Server.ConnectionOutcomes;
+using FinalFactory.Rendezvous.Server.Deployment;
 using FinalFactory.Rendezvous.Server.Http;
 using FinalFactory.Rendezvous.Server.JoinAttempts;
+using FinalFactory.Rendezvous.Server.Observability;
+using FinalFactory.Rendezvous.Server.Operations;
 using FinalFactory.Rendezvous.Server.Provisioning;
 using FinalFactory.Rendezvous.Server.Sessions;
 using FinalFactory.Rendezvous.Server.State;
 using FinalFactory.Rendezvous.Server.Transport;
+using Microsoft.AspNetCore.HttpOverrides;
 using Microsoft.OpenApi;
 
 WebApplicationBuilder builder = WebApplication.CreateBuilder(args);
+builder.Logging.AddFilter(
+    "Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware",
+    LogLevel.None);
 bool isOpenApiGeneration = string.Equals(
     System.Reflection.Assembly.GetEntryAssembly()?.GetName().Name,
     "GetDocument.Insider",
@@ -59,6 +67,14 @@ builder.Services.AddOpenApi("v1", static options =>
             In = ParameterLocation.Header,
             Description = "Attempt-scoped client capability returned only to the joining caller.",
         };
+        const string operatorSchemeName = "OperatorBearer";
+        document.Components.SecuritySchemes[operatorSchemeName] = new OpenApiSecurityScheme
+        {
+            Type = SecuritySchemeType.Http,
+            Scheme = "bearer",
+            BearerFormat = "rv1 operator credential",
+            Description = "Operator-only credential with an explicit permission set.",
+        };
 
         HashSet<string> securedOperations = new(StringComparer.Ordinal)
         {
@@ -67,8 +83,17 @@ builder.Services.AddOpenApi("v1", static options =>
             "UpdateSession",
             "DeleteSession",
         };
+        HashSet<string> operatorOperations = new(StringComparer.Ordinal)
+        {
+            "GetOperatorStatus",
+            "RevokeOperatorListing",
+            "RevokeOperatorPrincipal",
+            "RevokeOperatorSigningKey",
+            "BeginOperatorDrain",
+        };
         OpenApiSecuritySchemeReference reference = new(schemeName, document, null);
         OpenApiSecuritySchemeReference attemptReference = new(attemptSchemeName, document, null);
+        OpenApiSecuritySchemeReference operatorReference = new(operatorSchemeName, document, null);
         foreach (OpenApiPathItem path in document.Paths.Values)
         {
             if (path.Operations is null)
@@ -96,6 +121,60 @@ builder.Services.AddOpenApi("v1", static options =>
                     [attemptReference] = [],
                 });
             }
+
+            foreach (OpenApiOperation operation in path.Operations.Values.Where(
+                         operation => operatorOperations.Contains(
+                             operation.OperationId ?? string.Empty)))
+            {
+                operation.Security ??= [];
+                operation.Security.Add(new OpenApiSecurityRequirement
+                {
+                    [operatorReference] = [],
+                });
+            }
+
+            foreach (OpenApiOperation operation in path.Operations.Values)
+            {
+                if (operation.Responses is null)
+                {
+                    continue;
+                }
+
+                foreach ((string status, IOpenApiResponse response) in operation.Responses)
+                {
+                    if (response is not OpenApiResponse concreteResponse)
+                    {
+                        continue;
+                    }
+
+                    concreteResponse.Headers ??=
+                        new Dictionary<string, IOpenApiHeader>(StringComparer.OrdinalIgnoreCase);
+                    concreteResponse.Headers["X-Rendezvous-Correlation-ID"] = new OpenApiHeader
+                    {
+                        Description = "Safe request correlation identifier generated by the service.",
+                        Schema = new OpenApiSchema
+                        {
+                            Type = JsonSchemaType.String,
+                        },
+                    };
+                    if (string.Equals(
+                            status,
+                            StatusCodes.Status429TooManyRequests.ToString(
+                                System.Globalization.CultureInfo.InvariantCulture),
+                            StringComparison.Ordinal))
+                    {
+                        concreteResponse.Headers["Retry-After"] = new OpenApiHeader
+                        {
+                            Description = "Whole seconds before the caller should retry (1-60).",
+                            Schema = new OpenApiSchema
+                            {
+                                Type = JsonSchemaType.Integer,
+                                Format = "int32",
+                            },
+                        };
+                    }
+                }
+            }
         }
 
         return Task.CompletedTask;
@@ -107,15 +186,90 @@ builder.Services.Configure<RouteHandlerOptions>(static options =>
     options.ThrowOnBadRequest = true);
 builder.Services.AddProblemDetails();
 builder.Services.AddExceptionHandler<RendezvousExceptionHandler>();
+builder.WebHost.ConfigureKestrel(static options =>
+    options.Limits.MaxRequestBodySize = ContractLimits.HttpRequestMaxBytes);
+
+builder.Services
+    .AddOptions<AbuseProtectionOptions>()
+    .BindConfiguration(AbuseProtectionOptions.SectionName)
+    .ValidateDataAnnotations()
+    .Validate(
+        options => options.HttpOptionalRequestsPerWindow
+                   < options.HttpGlobalRequestsPerWindow,
+        "The optional HTTP request budget must leave global capacity for lease operations.")
+    .Validate(
+        options => options.HttpOptionalConcurrency < options.HttpGlobalConcurrency,
+        "The optional HTTP concurrency budget must leave global capacity for lease operations.")
+    .Validate(
+        options => options.HttpOptionalIpPrefixRequestsPerWindow
+                   < options.HttpIpPrefixRequestsPerWindow,
+        "The optional HTTP source budget must leave capacity for lease operations.")
+    .Validate(
+        options => options.HttpOptionalIpPrefixConcurrency
+                   < options.HttpIpPrefixConcurrency,
+        "The optional HTTP source concurrency must leave capacity for lease operations.")
+    .Validate(
+        options => options.CriticalTrackedKeyReserve >= 16
+                   && options.UdpTrackedKeyLimit + options.CriticalTrackedKeyReserve
+                   < options.MaxTrackedKeys,
+        "The tracked-key reserve must leave at least 16 keys for critical operations.")
+    .Validate(
+        options => options.TrustedProxyAddresses is { Length: <= 32 } addresses
+                   && addresses.All(
+                       static value => IPAddress.TryParse(value, out _)),
+        "Trusted proxy addresses must contain at most 32 literal IP addresses.")
+    .Validate(
+        options => options.OperatorAllowedAddresses is { Length: <= 32 } addresses
+                   && addresses.All(
+                       static value => IPAddress.TryParse(value, out _)),
+        "Operator allowed addresses must contain at most 32 literal IP addresses.")
+    .ValidateOnStart();
+builder.Services.AddSingleton<AbuseProtectionService>();
+builder.Services
+    .AddOptions<AuditOptions>()
+    .BindConfiguration(AuditOptions.SectionName)
+    .ValidateDataAnnotations()
+    .ValidateOnStart();
+AbuseProtectionOptions configuredAbuseProtection = builder.Configuration
+    .GetSection(AbuseProtectionOptions.SectionName)
+    .Get<AbuseProtectionOptions>() ?? new AbuseProtectionOptions();
+builder.Services.Configure<ForwardedHeadersOptions>(options =>
+    TrustedProxyForwarding.Configure(options, configuredAbuseProtection));
+
+DeploymentOptions deploymentOptions = builder.Configuration
+    .GetSection(DeploymentOptions.SectionName)
+    .Get<DeploymentOptions>() ?? new DeploymentOptions();
+if (!builder.Environment.IsDevelopment() && !isOpenApiGeneration)
+{
+    IReadOnlyList<string> deploymentErrors = deploymentOptions.ValidateProduction(
+        configuredAbuseProtection,
+        builder.Configuration["AllowedHosts"]);
+    if (deploymentErrors.Count > 0)
+    {
+        throw new DeploymentConfigurationException(deploymentErrors);
+    }
+}
+
+builder.Services.AddSingleton(Microsoft.Extensions.Options.Options.Create(deploymentOptions));
+builder.Services.Configure<HostOptions>(options =>
+    options.ShutdownTimeout = TimeSpan.FromSeconds(deploymentOptions.DrainDeadlineSeconds + 10));
 
 SystemRendezvousClock rendezvousClock = new();
-EphemeralStoreOptions stateOptions = new();
+EphemeralStoreOptions stateOptions = new()
+{
+    GracefulDrainLifetime = TimeSpan.FromSeconds(deploymentOptions.DrainDeadlineSeconds),
+};
 InMemoryEphemeralRendezvousStore stateStore = new(
     stateOptions,
     rendezvousClock,
     rendezvousClock);
+builder.Services.AddSingleton(stateStore);
 builder.Services.AddSingleton<IEphemeralRendezvousStore>(stateStore);
 builder.Services.AddSingleton<IWallClock>(rendezvousClock);
+builder.Services.AddSingleton<IMonotonicClock>(rendezvousClock);
+builder.Services.AddSingleton<RendezvousTelemetry>();
+builder.Services.AddSingleton<AuditTrail>();
+builder.Services.AddSingleton<RendezvousReadiness>();
 
 if (isOpenApiGeneration)
 {
@@ -148,6 +302,7 @@ else
     builder.Services.AddSingleton<JoinAttemptService>();
     builder.Services.AddSingleton<ConnectionOutcomeMetrics>();
     builder.Services.AddSingleton<ConnectionOutcomeService>();
+    builder.Services.AddSingleton<OperatorService>();
     builder.Services.AddSingleton(new ProvisioningReadiness(true));
 }
 
@@ -171,36 +326,24 @@ if (!isOpenApiGeneration)
     builder.Services.AddSingleton<NatMediationProcessor>();
     builder.Services.AddHostedService(static services =>
         services.GetRequiredService<UdpMediatorService>());
+    // Hosted services stop in reverse registration order. Drain must complete while
+    // Kestrel and the UDP mediator are still able to finish bounded in-flight work.
+    builder.Services.AddHostedService<GracefulDrainService>();
 }
 
 WebApplication app = builder.Build();
-app.Lifetime.ApplicationStopping.Register(() => stateStore.BeginDrain());
 
+if (TrustedProxyForwarding.IsEnabled(configuredAbuseProtection))
+{
+    app.UseForwardedHeaders();
+}
+app.UseMiddleware<TelemetryMiddleware>();
 app.UseExceptionHandler();
+app.UseMiddleware<HttpAbuseProtectionMiddleware>();
 app.MapOpenApi();
 app.MapRendezvousContractEndpoints();
-app.MapGet(
-        "/health/live",
-        static () => Results.Ok(new HealthResponse { Status = "live" }))
-    .Produces<HealthResponse>()
-    .WithName("GetLiveness")
-    .WithTags("Health");
-app.MapGet(
-    "/health/ready",
-    static (
-        UdpMediatorService mediator,
-        ProvisioningReadiness provisioning,
-        IEphemeralRendezvousStore state) =>
-        mediator.LocalEndpoint is null
-        || !provisioning.IsReady
-        || !state.IsAvailable
-        || state.IsDraining
-        ? Results.StatusCode(StatusCodes.Status503ServiceUnavailable)
-        : Results.Ok(new HealthResponse { Status = "ready" }))
-    .Produces<HealthResponse>()
-    .Produces(StatusCodes.Status503ServiceUnavailable)
-    .WithName("GetReadiness")
-    .WithTags("Health");
+app.MapOperatorEndpoints();
+app.MapRendezvousHealthEndpoints();
 
 await app.RunAsync();
 

src/FinalFactory.Rendezvous.Server/Provisioning/SecretProviders.cs

@@ -40,18 +40,32 @@ internal sealed class SecretMaterial : IDisposable
 
 internal sealed class EnvironmentSecretProvider : ISecretProvider
 {
-    private const string Prefix = "env:";
+    private const string EnvironmentPrefix = "env:";
+    private const string FilePrefix = "file:";
+    private const int MaximumSecretBytes = 4096;
 
     public bool TryGetSecret(string reference, out SecretMaterial? secret)
     {
         secret = null;
-        if (!reference.StartsWith(Prefix, StringComparison.Ordinal)
-            || reference.Length == Prefix.Length)
+        if (reference.StartsWith(EnvironmentPrefix, StringComparison.Ordinal)
+            && reference.Length > EnvironmentPrefix.Length)
         {
+            return TryGetEnvironmentSecret(reference[EnvironmentPrefix.Length..], out secret);
+        }
+
+        if (reference.StartsWith(FilePrefix, StringComparison.Ordinal)
+            && reference.Length > FilePrefix.Length)
+        {
+            return TryGetFileSecret(reference[FilePrefix.Length..], out secret);
+        }
+
         return false;
     }
 
-        string? encoded = Environment.GetEnvironmentVariable(reference[Prefix.Length..]);
+    private static bool TryGetEnvironmentSecret(string variableName, out SecretMaterial? secret)
+    {
+        secret = null;
+        string? encoded = Environment.GetEnvironmentVariable(variableName);
         if (string.IsNullOrEmpty(encoded))
         {
             return false;
@@ -60,6 +74,12 @@ internal sealed class EnvironmentSecretProvider : ISecretProvider
         try
         {
             byte[] bytes = Convert.FromBase64String(encoded);
+            if (bytes.Length is 0 or > MaximumSecretBytes)
+            {
+                CryptographicOperations.ZeroMemory(bytes);
+                return false;
+            }
+
             secret = new SecretMaterial(bytes);
             CryptographicOperations.ZeroMemory(bytes);
             return true;
@@ -69,6 +89,47 @@ internal sealed class EnvironmentSecretProvider : ISecretProvider
             return false;
         }
     }
+
+    private static bool TryGetFileSecret(string path, out SecretMaterial? secret)
+    {
+        secret = null;
+        byte[]? bytes = null;
+        try
+        {
+            FileInfo file = new(path);
+            if (!file.Exists
+                || !Path.IsPathFullyQualified(path)
+                || file.LinkTarget is not null
+                || file.Length is <= 0 or > MaximumSecretBytes)
+            {
+                return false;
+            }
+
+            bytes = File.ReadAllBytes(path);
+            if (bytes.Length is 0 or > MaximumSecretBytes)
+            {
+                return false;
+            }
+
+            secret = new SecretMaterial(bytes);
+            return true;
+        }
+        catch (Exception exception) when (exception is IOException
+                                           or UnauthorizedAccessException
+                                           or ArgumentException
+                                           or NotSupportedException
+                                           or System.Security.SecurityException)
+        {
+            return false;
+        }
+        finally
+        {
+            if (bytes is not null)
+            {
+                CryptographicOperations.ZeroMemory(bytes);
+            }
+        }
+    }
 }
 
 internal sealed class EphemeralDevelopmentSecretProvider : ISecretProvider, IDisposable

src/FinalFactory.Rendezvous.Server/Provisioning/SigningKeyRing.cs

@@ -142,8 +142,36 @@ internal sealed class SigningKeyRing : IDisposable
         return VerificationKeyLookup.Available;
     }
 
-    public bool Revoke(string keyId) =>
-        _keys.ContainsKey(keyId) && _runtimeRevocations.TryAdd(keyId, 0);
+    public bool Revoke(string keyId)
+    {
+        if (!_keys.ContainsKey(keyId))
+        {
+            return false;
+        }
+
+        _runtimeRevocations.TryAdd(keyId, 0);
+        return true;
+    }
+
+    public IReadOnlyList<SigningKeyStatus> GetStatuses(DateTimeOffset now) => _keys.Values
+        .OrderBy(static key => key.KeyId, StringComparer.Ordinal)
+        .Select(key => new SigningKeyStatus(
+            key.KeyId,
+            IsRevoked(key)
+                ? "revoked"
+                : now < key.NotBefore
+                    ? "not-yet-valid"
+                    : now < key.SignUntil
+                        ? "signing"
+                        : now < key.VerifyUntil
+                            ? "verify-only"
+                            : "retired",
+            key.SignUntil,
+            key.VerifyUntil,
+            key.GameId,
+            key.EnvironmentId,
+            key.CredentialKinds.Select(static kind => kind.ToString()).Order().ToArray()))
+        .ToArray();
 
     public void Dispose()
     {
@@ -210,6 +238,15 @@ internal sealed class SigningKeyRing : IDisposable
     }
 }
 
+internal sealed record SigningKeyStatus(
+    string KeyId,
+    string Status,
+    DateTimeOffset SignUntil,
+    DateTimeOffset VerifyUntil,
+    string? GameId,
+    string? EnvironmentId,
+    IReadOnlyList<string> CredentialKinds);
+
 internal sealed class SigningKey : IDisposable
 {
     private byte[]? _material;

src/FinalFactory.Rendezvous.Server/State/EphemeralStateContracts.cs

@@ -297,6 +297,7 @@ internal sealed record StoredJoinAttempt
     public required SecretFingerprint ConnectionTicketFingerprint { get; init; }
     public NetworkEndpoint? DedicatedFallback { get; init; }
     public required DateTimeOffset ExpiresAt { get; init; }
+    public required TimeSpan CreatedAtMonotonic { get; init; }
     public required DateTimeOffset ConnectionTicketExpiresAt { get; init; }
     public AttemptEndpointBinding? HostEndpoint { get; init; }
     public AttemptEndpointBinding? ClientEndpoint { get; init; }

src/FinalFactory.Rendezvous.Server/State/InMemoryEphemeralRendezvousStore.cs

@@ -15,6 +15,7 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
     private readonly Dictionary<MediationHandle, SessionListingId> _presenceHandles = [];
     private readonly Dictionary<MediationHandle, PresenceEntry> _presence = [];
     private readonly Dictionary<JoinAttemptId, AttemptEntry> _attempts = [];
+    private readonly PriorityQueue<AttemptExpiry, long> _attemptExpiries = new();
     private readonly Dictionary<JoinAttemptId, OutcomeReportEntry> _outcomeReports = [];
     private readonly Dictionary<MediationHandle, JoinAttemptId> _attemptHandles = [];
     private readonly Dictionary<string, IdempotencyEntry> _idempotency = new(StringComparer.Ordinal);
@@ -23,7 +24,10 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
     private TimeSpan? _drainDeadline;
     private TimeSpan _nextUdpMaintenance;
     private long _maintenanceSweepCount;
+    private long _expiryChurn;
     private bool _available = true;
+    private EphemeralStoreSnapshot? _metricsSnapshot;
+    private TimeSpan _metricsSnapshotAt = TimeSpan.MinValue;
 
     public InMemoryEphemeralRendezvousStore(
         EphemeralStoreOptions options,
@@ -66,6 +70,59 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
         }
     }
 
+    internal EphemeralStoreSnapshot GetSnapshot()
+    {
+        lock (_gate)
+        {
+            TimeSpan now = _monotonicClock.Elapsed;
+            Cleanup(now);
+            EphemeralStoreSnapshot snapshot = CreateSnapshot();
+            _metricsSnapshot = snapshot;
+            _metricsSnapshotAt = now;
+            return snapshot;
+        }
+    }
+
+    internal int GetActiveJoinAttemptCountForDrain()
+    {
+        lock (_gate)
+        {
+            _expiryChurn += RemoveExpiredAttempts(_monotonicClock.Elapsed);
+            return _attempts.Count;
+        }
+    }
+
+    internal EphemeralStoreSnapshot GetMetricsSnapshot()
+    {
+        lock (_gate)
+        {
+            TimeSpan now = _monotonicClock.Elapsed;
+            if (_metricsSnapshot is null
+                || now < _metricsSnapshotAt
+                || now - _metricsSnapshotAt >= TimeSpan.FromMilliseconds(100))
+            {
+                Cleanup(now);
+                _metricsSnapshot = CreateSnapshot();
+                _metricsSnapshotAt = now;
+            }
+
+            return _metricsSnapshot;
+        }
+    }
+
+    private EphemeralStoreSnapshot CreateSnapshot() => new(
+        _listings.Count,
+        _presence.Count,
+        _attempts.Count,
+        _outcomeReports.Count,
+        _replay.Count,
+        _revocations.Count,
+        _idempotency.Count,
+        _maintenanceSweepCount,
+        _expiryChurn,
+        _available,
+        _drainDeadline.HasValue);
+
     public StoreResult<StoredListing> CreateListing(
         CreateListingCommand command,
         CancellationToken cancellationToken = default) => Atomic<StoredListing>(now =>
@@ -400,9 +457,13 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
 
         AttemptEntry attempt = new(
             command,
+            now,
             now + _options.JoinAttemptLifetime,
             WallDeadline(now, _options.JoinAttemptLifetime));
         _attempts.Add(command.AttemptId, attempt);
+        _attemptExpiries.Enqueue(
+            new AttemptExpiry(command.AttemptId, attempt.Deadline),
+            attempt.Deadline.Ticks);
         _outcomeReports.Add(command.AttemptId, new(
             command.ListingId,
             command.ClientSubject,
@@ -729,6 +790,10 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
             return new(StoreResultCode.CapacityExceeded);
         }
 
+        int activeResourcesBefore = _listings.Count
+            + _presence.Count
+            + _attempts.Count
+            + _outcomeReports.Count;
         _revocations[subject] = now + lifetime;
         SessionListingId[] listings = _listings
             .Where(item => string.Equals(item.Value.Definition.OwnerSubject, subject, StringComparison.Ordinal))
@@ -756,7 +821,11 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
             _outcomeReports.Remove(attemptId);
         }
 
-        return new(StoreResultCode.Success, listings.Length + attempts.Length);
+        int activeResourcesAfter = _listings.Count
+            + _presence.Count
+            + _attempts.Count
+            + _outcomeReports.Count;
+        return new(StoreResultCode.Success, activeResourcesBefore - activeResourcesAfter);
     }, cancellationToken);
 
     public void BeginDrain(CancellationToken cancellationToken = default)
@@ -768,6 +837,7 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
             if (!_drainDeadline.HasValue)
             {
                 _drainDeadline = _monotonicClock.Elapsed + _options.GracefulDrainLifetime;
+                _metricsSnapshot = null;
             }
         }
     }
@@ -778,6 +848,7 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
         {
             _available = false;
             ClearActiveState();
+            _metricsSnapshot = null;
         }
     }
 
@@ -801,7 +872,9 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
                 _nextUdpMaintenance = now + UdpMaintenanceInterval;
             }
 
-            return operation(now);
+            StoreResult<T> result = operation(now);
+            _metricsSnapshot = null;
+            return result;
         }
     }
 
@@ -838,44 +911,46 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
             ClearActiveState();
         }
 
-        RemoveExpired(_revocations, now);
-        RemoveExpired(_replay, now);
-        foreach (string key in _idempotency
+        _expiryChurn += RemoveExpired(_revocations, now);
+        _expiryChurn += RemoveExpired(_replay, now);
+        string[] expiredIdempotency = _idempotency
             .Where(item => item.Value.Deadline <= now)
             .Select(static item => item.Key)
-                     .ToArray())
+            .ToArray();
+        _expiryChurn += expiredIdempotency.Length;
+        foreach (string key in expiredIdempotency)
         {
             _idempotency.Remove(key);
         }
 
-        foreach (MediationHandle handle in _presence
+        MediationHandle[] expiredPresence = _presence
             .Where(item => item.Value.Deadline <= now)
             .Select(static item => item.Key)
-                     .ToArray())
+            .ToArray();
+        _expiryChurn += expiredPresence.Length;
+        foreach (MediationHandle handle in expiredPresence)
         {
             _presence.Remove(handle);
         }
 
-        foreach (JoinAttemptId attemptId in _attempts
-                     .Where(item => item.Value.Deadline <= now)
-                     .Select(static item => item.Key)
-                     .ToArray())
-        {
-            RemoveAttempt(attemptId);
-        }
+        _expiryChurn += RemoveExpiredAttempts(now);
 
-        foreach (JoinAttemptId attemptId in _outcomeReports
+        JoinAttemptId[] expiredOutcomes = _outcomeReports
             .Where(item => item.Value.Deadline <= now)
             .Select(static item => item.Key)
-                     .ToArray())
+            .ToArray();
+        _expiryChurn += expiredOutcomes.Length;
+        foreach (JoinAttemptId attemptId in expiredOutcomes)
         {
             _outcomeReports.Remove(attemptId);
         }
 
-        foreach (SessionListingId listingId in _listings
+        SessionListingId[] expiredListings = _listings
             .Where(item => item.Value.LeaseDeadline <= now)
             .Select(static item => item.Key)
-                     .ToArray())
+            .ToArray();
+        _expiryChurn += expiredListings.Length;
+        foreach (SessionListingId listingId in expiredListings)
         {
             RemoveListing(listingId);
         }
@@ -888,6 +963,7 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
         _presenceHandles.Clear();
         _presence.Clear();
         _attempts.Clear();
+        _attemptExpiries.Clear();
         _outcomeReports.Clear();
         _attemptHandles.Clear();
         _idempotency.Clear();
@@ -930,6 +1006,24 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
         }
     }
 
+    private int RemoveExpiredAttempts(TimeSpan now)
+    {
+        int removed = 0;
+        while (_attemptExpiries.TryPeek(out AttemptExpiry candidate, out long deadlineTicks)
+               && deadlineTicks <= now.Ticks)
+        {
+            _attemptExpiries.Dequeue();
+            if (_attempts.TryGetValue(candidate.AttemptId, out AttemptEntry? current)
+                && current.Deadline == candidate.Deadline)
+            {
+                RemoveAttempt(candidate.AttemptId);
+                removed++;
+            }
+        }
+
+        return removed;
+    }
+
     private bool HandleExists(MediationHandle handle) =>
         _presenceHandles.ContainsKey(handle) || _attemptHandles.ContainsKey(handle);
 
@@ -959,6 +1053,7 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
         ClientCapabilityFingerprint = entry.Command.ClientCapabilityFingerprint,
         ConnectionTicketFingerprint = entry.Command.ConnectionTicketFingerprint,
         DedicatedFallback = StoredListing.CopyEndpoint(entry.Command.DedicatedFallback),
+        CreatedAtMonotonic = entry.CreatedAtMonotonic,
         ExpiresAt = entry.WallExpiresAt,
         ConnectionTicketExpiresAt = entry.TicketWallExpiresAt ?? default,
         HostEndpoint = entry.HostEndpoint,
@@ -968,15 +1063,18 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
         IsCancelled = entry.IsCancelled,
     };
 
-    private static void RemoveExpired(Dictionary<string, TimeSpan> entries, TimeSpan now)
+    private static int RemoveExpired(Dictionary<string, TimeSpan> entries, TimeSpan now)
     {
-        foreach (string key in entries
+        string[] expired = entries
             .Where(item => item.Value <= now)
             .Select(static item => item.Key)
-                     .ToArray())
+            .ToArray();
+        foreach (string key in expired)
         {
             entries.Remove(key);
         }
+
+        return expired.Length;
     }
 
     private static void ValidateListing(ListingDefinition listing)
@@ -1101,10 +1199,12 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
 
     private sealed class AttemptEntry(
         CreateJoinAttemptCommand command,
+        TimeSpan createdAtMonotonic,
         TimeSpan deadline,
         DateTimeOffset wallExpiresAt)
     {
         public CreateJoinAttemptCommand Command { get; } = command;
+        public TimeSpan CreatedAtMonotonic { get; } = createdAtMonotonic;
         public SecretFingerprint HostCapabilityFingerprint { get; } = command.HostCapabilityFingerprint;
         public SecretFingerprint ClientCapabilityFingerprint { get; } = command.ClientCapabilityFingerprint;
         public SecretFingerprint ConnectionTicketFingerprint { get; } = command.ConnectionTicketFingerprint;
@@ -1119,6 +1219,8 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
         public bool IsCancelled { get; set; }
     }
 
+    private readonly record struct AttemptExpiry(JoinAttemptId AttemptId, TimeSpan Deadline);
+
     private sealed class OutcomeReportEntry(
         SessionListingId listingId,
         string clientSubject,
@@ -1137,3 +1239,16 @@ internal sealed class InMemoryEphemeralRendezvousStore : IEphemeralRendezvousSto
         object ResourceId,
         TimeSpan Deadline);
 }
+
+internal sealed record EphemeralStoreSnapshot(
+    int ActiveListings,
+    int FreshPresenceBindings,
+    int ActiveJoinAttempts,
+    int RetainedOutcomeReports,
+    int ReplayMarkers,
+    int PrincipalRevocations,
+    int IdempotencyEntries,
+    long MaintenanceSweeps,
+    long ExpiryChurn,
+    bool IsAvailable,
+    bool IsDraining);

src/FinalFactory.Rendezvous.Server/Transport/NatMediationProcessor.cs

@@ -1,7 +1,10 @@
+using System.Diagnostics;
 using System.Net;
 using System.Net.Sockets;
 using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Abuse;
 using FinalFactory.Rendezvous.Server.JoinAttempts;
+using FinalFactory.Rendezvous.Server.Observability;
 using FinalFactory.Rendezvous.Server.Sessions;
 using FinalFactory.Rendezvous.Server.State;
 
@@ -36,7 +39,10 @@ internal enum NatMediationResult
 internal sealed class NatMediationProcessor(
     IEphemeralRendezvousStore store,
     ISessionCapabilityService capabilities,
-    JoinAttemptService joinAttempts)
+    JoinAttemptService joinAttempts,
+    AbuseProtectionService? abuseProtection = null,
+    RendezvousTelemetry? telemetry = null,
+    IMonotonicClock? monotonicClock = null)
 {
     public NatMediationResult ProcessDatagram(
         ReadOnlySpan<byte> encoded,
@@ -44,6 +50,49 @@ internal sealed class NatMediationProcessor(
         INatIntroductionSink introductionSink,
         CancellationToken cancellationToken = default)
     {
+        if (!TryAcceptIngress(observedPublicEndpoint, "frozen"))
+        {
+            return NatMediationResult.Dropped;
+        }
+
+        return ProcessDatagramAfterIngress(
+            encoded,
+            observedPublicEndpoint,
+            introductionSink,
+            cancellationToken);
+    }
+
+    internal bool TryAcceptIngress(IPEndPoint observedPublicEndpoint, string operation) =>
+        abuseProtection is null
+        || abuseProtection.TryAcceptUdpIngress(observedPublicEndpoint.Address, operation);
+
+    internal NatMediationResult ProcessDatagramAfterIngress(
+        ReadOnlySpan<byte> encoded,
+        IPEndPoint observedPublicEndpoint,
+        INatIntroductionSink introductionSink,
+        CancellationToken cancellationToken = default)
+    {
+        long started = Stopwatch.GetTimestamp();
+        using Activity? activity = telemetry?.StartActivity("UDP frozen", ActivityKind.Server);
+        NatMediationResult result = ProcessDatagramCore(
+            encoded,
+            observedPublicEndpoint,
+            introductionSink,
+            cancellationToken);
+        telemetry?.RecordUdp(
+            "frozen",
+            result.ToString(),
+            Stopwatch.GetElapsedTime(started).TotalMilliseconds);
+        return result;
+    }
+
+    private NatMediationResult ProcessDatagramCore(
+        ReadOnlySpan<byte> encoded,
+        IPEndPoint observedPublicEndpoint,
+        INatIntroductionSink introductionSink,
+        CancellationToken cancellationToken)
+    {
+
         if (!RendezvousUdpCodec.TryDecode(encoded, out PresenceDatagram? datagram, out _)
             || datagram is null
             || datagram.Capability.Length != ContractLimits.DerivedCredentialCharacters
@@ -63,7 +112,7 @@ internal sealed class NatMediationProcessor(
             return NatMediationResult.Dropped;
         }
 
-        NatMediationResult result = ProcessRequest(
+        NatMediationResult result = ProcessRequestCore(
             claimedLocalEndpoint,
             observedPublicEndpoint,
             NatPunchRequestTokenCodec.Encode(role, datagram.MediationHandle, datagram.Capability),
@@ -76,7 +125,7 @@ internal sealed class NatMediationProcessor(
             return result;
         }
 
-        return ProcessRequest(
+        return ProcessRequestCore(
             claimedLocalEndpoint,
             observedPublicEndpoint,
             NatPunchRequestTokenCodec.Encode(
@@ -98,6 +147,49 @@ internal sealed class NatMediationProcessor(
         ArgumentNullException.ThrowIfNull(observedPublicEndpoint);
         ArgumentNullException.ThrowIfNull(introductionSink);
 
+        if (!TryAcceptIngress(observedPublicEndpoint, "litenet-or-invalid"))
+        {
+            return NatMediationResult.Dropped;
+        }
+
+        return ProcessRequestAfterIngress(
+            claimedLocalEndpoint,
+            observedPublicEndpoint,
+            token,
+            introductionSink,
+            cancellationToken);
+    }
+
+    internal NatMediationResult ProcessRequestAfterIngress(
+        IPEndPoint claimedLocalEndpoint,
+        IPEndPoint observedPublicEndpoint,
+        string token,
+        INatIntroductionSink introductionSink,
+        CancellationToken cancellationToken = default)
+    {
+        long started = Stopwatch.GetTimestamp();
+        using Activity? activity = telemetry?.StartActivity("UDP litenet", ActivityKind.Server);
+        NatMediationResult result = ProcessRequestCore(
+            claimedLocalEndpoint,
+            observedPublicEndpoint,
+            token,
+            introductionSink,
+            cancellationToken);
+        telemetry?.RecordUdp(
+            "litenet",
+            result.ToString(),
+            Stopwatch.GetElapsedTime(started).TotalMilliseconds);
+        return result;
+    }
+
+    private NatMediationResult ProcessRequestCore(
+        IPEndPoint claimedLocalEndpoint,
+        IPEndPoint observedPublicEndpoint,
+        string token,
+        INatIntroductionSink introductionSink,
+        CancellationToken cancellationToken)
+    {
+
         if (!NatPunchRequestTokenCodec.TryDecode(token, out NatPunchRequestToken? request)
             || request is null
             || !TryCreateObservedEndpoint(observedPublicEndpoint, out ObservedEndpoint publicEndpoint)
@@ -106,6 +198,17 @@ internal sealed class NatMediationProcessor(
             return NatMediationResult.Dropped;
         }
 
+        string operation = request.Role.ToString();
+        if (abuseProtection is not null
+            && !abuseProtection.TryAcceptUdpIdentity(
+                operation,
+                observedPublicEndpoint.Address,
+                request.Capability,
+                request.MediationHandle.ToString()))
+        {
+            return NatMediationResult.Dropped;
+        }
+
         ObservedEndpoint? localEndpoint = TryCreatePrivateCandidate(
             claimedLocalEndpoint,
             publicEndpoint.AddressFamily,
@@ -186,6 +289,14 @@ internal sealed class NatMediationProcessor(
         try
         {
             introductionSink.Introduce(CreatePlan(consumed.Value, ticket.Value));
+            if (telemetry is not null && monotonicClock is not null)
+            {
+                telemetry.RecordPairingLatency(Math.Max(
+                    0,
+                    (monotonicClock.Elapsed - consumed.Value.Attempt.CreatedAtMonotonic)
+                    .TotalMilliseconds));
+            }
+
             return NatMediationResult.Introduced;
         }
         catch (Exception exception) when (exception is SocketException

src/FinalFactory.Rendezvous.Server/Transport/UdpMediatorService.cs

@@ -172,12 +172,21 @@ internal sealed partial class UdpMediatorService : BackgroundService
             bool isFrozenEnvelope = length >= 2
                 && data[0] == RendezvousUdpCodec.MagicFirst
                 && data[1] == RendezvousUdpCodec.MagicSecond;
+            if (!processor.TryAcceptIngress(
+                    endPoint,
+                    isFrozenEnvelope ? "frozen" : "litenet-or-invalid"))
+            {
+                Drop(ref length);
+                return;
+            }
+
             INatIntroductionSink? sink = _sink;
             if (isFrozenEnvelope)
             {
                 if (sink is not null)
                 {
-                    _ = processor.ProcessDatagram(data.AsSpan(0, length), endPoint, sink);
+                    _ = processor.ProcessDatagramAfterIngress(
+                        data.AsSpan(0, length), endPoint, sink);
                 }
             }
             else if (sink is not null
@@ -188,7 +197,8 @@ internal sealed partial class UdpMediatorService : BackgroundService
                      && claimedLocalEndpoint is not null
                      && token is not null)
             {
-                _ = processor.ProcessRequest(claimedLocalEndpoint, endPoint, token, sink);
+                _ = processor.ProcessRequestAfterIngress(
+                    claimedLocalEndpoint, endPoint, token, sink);
             }
 
             // Every inbound packet is consumed here. NatPunchModule is used only for outbound introductions.

src/FinalFactory.Rendezvous.Server/appsettings.Development.json

@@ -1,5 +1,8 @@
 {
   "Rendezvous": {
+    "AbuseProtection": {
+      "OperatorAllowedAddresses": ["127.0.0.1", "::1"]
+    },
     "Provisioning": {
       "Issuer": "final-factory-rendezvous-development",
       "Audience": "final-factory-rendezvous",
@@ -14,6 +17,14 @@
           "NotBefore": "2025-01-01T00:00:00Z",
           "SignUntil": "2035-01-01T00:00:00Z",
           "VerifyUntil": "2035-01-02T00:00:00Z"
+        },
+        {
+          "KeyId": "development-operator-1",
+          "SecretReference": "development:ephemeral/rendezvous-operator-signing",
+          "CredentialKinds": ["Operator"],
+          "NotBefore": "2025-01-01T00:00:00Z",
+          "SignUntil": "2035-01-01T00:00:00Z",
+          "VerifyUntil": "2035-01-02T00:00:00Z"
         }
       ],
       "Games": [

src/FinalFactory.Rendezvous.Server/appsettings.json

@@ -1,10 +1,60 @@
 {
   "Rendezvous": {
+    "Deployment": {
+      "PublicHttpBaseUrl": "",
+      "PublicUdpHost": "",
+      "PublicUdpPort": 9050,
+      "DrainDeadlineSeconds": 30,
+      "MinimumDrainSeconds": 1,
+      "SingleActiveInstance": true,
+      "AllowPrivatePublicEndpoints": false
+    },
     "Udp": {
       "ListenAddress": "0.0.0.0",
       "Port": 9050,
       "MaxDatagramsPerPoll": 256,
       "PollIntervalMilliseconds": 2
+    },
+    "Audit": {
+      "MaxEntries": 10000,
+      "RetentionDays": 30
+    },
+    "AbuseProtection": {
+      "WindowSeconds": 1,
+      "MaxTrackedKeys": 100000,
+      "CriticalTrackedKeyReserve": 2048,
+      "UdpTrackedKeyLimit": 70000,
+      "TrustedProxyAddresses": [],
+      "OperatorAllowedAddresses": [],
+      "HealthGlobalRequestsPerWindow": 1000,
+      "HealthGlobalConcurrency": 32,
+      "HealthIpPrefixRequestsPerWindow": 120,
+      "HealthIpPrefixConcurrency": 8,
+      "OperatorGlobalRequestsPerWindow": 1000,
+      "OperatorGlobalConcurrency": 32,
+      "OperatorIpPrefixRequestsPerWindow": 120,
+      "OperatorIpPrefixConcurrency": 8,
+      "HttpGlobalRequestsPerWindow": 20000,
+      "HttpOptionalRequestsPerWindow": 18000,
+      "HttpIpPrefixRequestsPerWindow": 500,
+      "HttpOptionalIpPrefixRequestsPerWindow": 450,
+      "HttpOperationRequestsPerWindow": 5000,
+      "HttpTenantRequestsPerWindow": 2000,
+      "HttpPrincipalRequestsPerWindow": 500,
+      "HttpResourceRequestsPerWindow": 200,
+      "HttpGlobalConcurrency": 1024,
+      "HttpOptionalConcurrency": 768,
+      "HttpIpPrefixConcurrency": 64,
+      "HttpOptionalIpPrefixConcurrency": 48,
+      "HttpOperationConcurrency": 256,
+      "HttpTenantConcurrency": 256,
+      "HttpPrincipalConcurrency": 32,
+      "HttpResourceConcurrency": 16,
+      "UdpGlobalDatagramsPerWindow": 100000,
+      "UdpIpPrefixDatagramsPerWindow": 2000,
+      "UdpOperationDatagramsPerWindow": 50000,
+      "UdpCapabilityDatagramsPerWindow": 120,
+      "UdpResourceDatagramsPerWindow": 240
     }
   },
   "Logging": {

tests/FinalFactory.Rendezvous.Tests/Client/RendezvousClientIntegrationTests.cs

@@ -1,5 +1,6 @@
 using FinalFactory.Rendezvous.Client;
 using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Abuse;
 using FinalFactory.Rendezvous.Server.Browser;
 using FinalFactory.Rendezvous.Server.Http;
 using FinalFactory.Rendezvous.Server.Provisioning;
@@ -159,6 +160,8 @@ public sealed class RendezvousClientIntegrationTests
                 options.ThrowOnBadRequest = true);
             builder.Services.AddProblemDetails();
             builder.Services.AddExceptionHandler<RendezvousExceptionHandler>();
+            builder.Services.AddOptions<AbuseProtectionOptions>();
+            builder.Services.AddSingleton<AbuseProtectionService>();
             builder.Services.AddSingleton(provisioning);
             builder.Services.AddSingleton(provisioning.Credentials);
             builder.Services.AddSingleton(provisioning.PublisherAuthorization);
@@ -173,6 +176,7 @@ public sealed class RendezvousClientIntegrationTests
 
             WebApplication app = builder.Build();
             app.UseExceptionHandler();
+            app.UseMiddleware<HttpAbuseProtectionMiddleware>();
             app.MapRendezvousContractEndpoints();
             await app.StartAsync();
             IServer server = app.Services.GetRequiredService<IServer>();

tests/FinalFactory.Rendezvous.Tests/Contracts/OpenApiCompatibilityTests.cs

@@ -11,6 +11,11 @@ public sealed class OpenApiCompatibilityTests
         "/v1/join-attempts",
         "/v1/join-attempts/{attemptId}",
         "/v1/join-attempts/{attemptId}/outcome",
+        "/v1/operator/drain",
+        "/v1/operator/keys/revoke",
+        "/v1/operator/listings/revoke",
+        "/v1/operator/principals/revoke",
+        "/v1/operator/status",
         "/v1/sessions",
         "/v1/sessions/{listingId}",
         "/v1/sessions/{listingId}/join-attempts",
@@ -104,6 +109,11 @@ public sealed class OpenApiCompatibilityTests
         Assert.Equal(
             "X-Rendezvous-Client-Punch-Capability",
             attemptCapability.GetProperty("name").GetString());
+        JsonElement operatorBearer = root.GetProperty("components")
+            .GetProperty("securitySchemes")
+            .GetProperty("OperatorBearer");
+        Assert.Equal("http", operatorBearer.GetProperty("type").GetString());
+        Assert.Equal("bearer", operatorBearer.GetProperty("scheme").GetString());
         (string Path, string Method)[] publisherOperations =
         [
             ("/v1/sessions", "post"),
@@ -120,6 +130,23 @@ public sealed class OpenApiCompatibilityTests
             Assert.True(security[0].TryGetProperty("PublisherBearer", out _));
         }
 
+        (string Path, string Method)[] operatorOperations =
+        [
+            ("/v1/operator/status", "get"),
+            ("/v1/operator/listings/revoke", "post"),
+            ("/v1/operator/principals/revoke", "post"),
+            ("/v1/operator/keys/revoke", "post"),
+            ("/v1/operator/drain", "post"),
+        ];
+        foreach ((string operationPath, string method) in operatorOperations)
+        {
+            JsonElement security = root.GetProperty("paths")
+                .GetProperty(operationPath)
+                .GetProperty(method)
+                .GetProperty("security");
+            Assert.True(security[0].TryGetProperty("OperatorBearer", out _));
+        }
+
         JsonElement cancelParameters = root.GetProperty("paths")
             .GetProperty("/v1/join-attempts/{attemptId}")
             .GetProperty("delete")
@@ -149,5 +176,58 @@ public sealed class OpenApiCompatibilityTests
             parameter.GetProperty("in").GetString() == "header"
             && parameter.GetProperty("name").GetString() == "X-Rendezvous-Lease-Token");
         Assert.True(leaseToken.GetProperty("required").GetBoolean());
+
+        int overloadContracts = 0;
+        foreach (JsonProperty pathItem in root.GetProperty("paths").EnumerateObject())
+        {
+            foreach (JsonProperty operation in pathItem.Value.EnumerateObject().Where(
+                         static item => item.Name is "get" or "post" or "put" or "delete"))
+            {
+                JsonElement responses = operation.Value.GetProperty("responses");
+                foreach (JsonProperty response in responses.EnumerateObject())
+                {
+                    JsonElement correlation = response.Value.GetProperty("headers")
+                        .GetProperty("X-Rendezvous-Correlation-ID");
+                    Assert.Equal(
+                        "string",
+                        correlation.GetProperty("schema").GetProperty("type").GetString());
+                }
+
+                if (!responses.TryGetProperty("429", out JsonElement overloaded))
+                {
+                    continue;
+                }
+
+                overloadContracts++;
+                JsonElement retryAfter = overloaded.GetProperty("headers")
+                    .GetProperty("Retry-After");
+                Assert.Equal(
+                    "integer",
+                    retryAfter.GetProperty("schema").GetProperty("type").GetString());
+            }
+        }
+
+        Assert.Equal(17, overloadContracts);
+        (string Path, string Method)[] bodyOperations =
+        [
+            ("/v1/sessions", "post"),
+            ("/v1/sessions/{listingId}/renew", "post"),
+            ("/v1/sessions/{listingId}", "put"),
+            ("/v1/sessions/{listingId}", "delete"),
+            ("/v1/join-attempts", "post"),
+            ("/v1/join-attempts/{attemptId}/outcome", "post"),
+            ("/v1/operator/listings/revoke", "post"),
+            ("/v1/operator/principals/revoke", "post"),
+            ("/v1/operator/keys/revoke", "post"),
+            ("/v1/operator/drain", "post"),
+        ];
+        foreach ((string operationPath, string method) in bodyOperations)
+        {
+            Assert.True(root.GetProperty("paths")
+                .GetProperty(operationPath)
+                .GetProperty(method)
+                .GetProperty("responses")
+                .TryGetProperty("413", out _));
+        }
     }
 }

tests/FinalFactory.Rendezvous.Tests/Deployment/DeploymentOptionsTests.cs

@@ -0,0 +1,137 @@
+using FinalFactory.Rendezvous.Server.Abuse;
+using FinalFactory.Rendezvous.Server.Deployment;
+
+namespace FinalFactory.Rendezvous.Tests.Deployment;
+
+public sealed class DeploymentOptionsTests
+{
+    [Fact]
+    public void ProductionConfigurationAcceptsExplicitPublicEndpointsAndTrustBoundary()
+    {
+        DeploymentOptions options = ValidOptions();
+        AbuseProtectionOptions abuse = new()
+        {
+            TrustedProxyAddresses = ["192.0.2.10"],
+        };
+
+        IReadOnlyList<string> errors = options.ValidateProduction(
+            abuse,
+            "rendezvous.finalfactory.at");
+
+        Assert.Empty(errors);
+    }
+
+    [Fact]
+    public void ProductionConfigurationRejectsUnsafeAndAmbiguousDefaults()
+    {
+        DeploymentOptions options = new()
+        {
+            SingleActiveInstance = false,
+        };
+
+        IReadOnlyList<string> errors = options.ValidateProduction(
+            new AbuseProtectionOptions(),
+            "*");
+
+        Assert.Contains(errors, error => error.Contains("SingleActiveInstance", StringComparison.Ordinal));
+        Assert.Contains(errors, error => error.Contains("PublicHttpBaseUrl", StringComparison.Ordinal));
+        Assert.Contains(errors, error => error.Contains("PublicUdpHost", StringComparison.Ordinal));
+        Assert.Contains(errors, error => error.Contains("TrustedProxyAddresses", StringComparison.Ordinal));
+        Assert.Contains(errors, error => error.Contains("AllowedHosts", StringComparison.Ordinal));
+    }
+
+    [Theory]
+    [InlineData("http://rendezvous.example.com/")]
+    [InlineData("https://user@example.com/")]
+    [InlineData("https://rendezvous.example.com/path")]
+    [InlineData("https://localhost/")]
+    [InlineData("https://10.0.0.1/")]
+    [InlineData("https://192.0.2.10/")]
+    [InlineData("https://[::ffff:10.0.0.1]/")]
+    [InlineData("https://[ff02::1]/")]
+    [InlineData("https://rendezvous.invalid/")]
+    public void ProductionConfigurationRejectsUnsafeHttpEndpoint(string endpoint)
+    {
+        DeploymentOptions options = ValidOptions() with { PublicHttpBaseUrl = endpoint };
+
+        IReadOnlyList<string> errors = options.ValidateProduction(
+            new AbuseProtectionOptions { TrustedProxyAddresses = ["192.0.2.10"] },
+            "rendezvous.finalfactory.at");
+
+        Assert.Contains(errors, error => error.Contains("PublicHttpBaseUrl", StringComparison.Ordinal));
+    }
+
+    [Theory]
+    [InlineData("0.1.2.3")]
+    [InlineData("100.64.0.1")]
+    [InlineData("192.0.2.1")]
+    [InlineData("198.18.0.1")]
+    [InlineData("198.51.100.1")]
+    [InlineData("203.0.113.1")]
+    [InlineData("224.0.0.1")]
+    [InlineData("255.255.255.255")]
+    [InlineData("::ffff:192.168.1.1")]
+    [InlineData("2001:db8::1")]
+    [InlineData("ff02::1")]
+    [InlineData("rendezvous.example.com")]
+    [InlineData("rendezvous.home.arpa")]
+    [InlineData("rendezvous.alt")]
+    [InlineData("service.test")]
+    public void ProductionConfigurationRejectsNonPublicUdpEndpoint(string endpoint)
+    {
+        DeploymentOptions options = ValidOptions() with { PublicUdpHost = endpoint };
+
+        IReadOnlyList<string> errors = options.ValidateProduction(
+            new AbuseProtectionOptions { TrustedProxyAddresses = ["192.0.2.10"] },
+            "rendezvous.finalfactory.at");
+
+        Assert.Contains(errors, error => error.Contains("PublicUdpHost", StringComparison.Ordinal));
+    }
+
+    [Fact]
+    public void IsolatedSmokeTestRequiresExplicitPrivateEndpointOverride()
+    {
+        DeploymentOptions options = ValidOptions() with
+        {
+            PublicHttpBaseUrl = "https://localhost/",
+            PublicUdpHost = "127.0.0.1",
+            AllowPrivatePublicEndpoints = true,
+        };
+
+        IReadOnlyList<string> errors = options.ValidateProduction(
+            new AbuseProtectionOptions { TrustedProxyAddresses = ["127.0.0.1"] },
+            "localhost");
+
+        Assert.Empty(errors);
+    }
+
+    [Fact]
+    public void ProductionConfigurationRejectsInvalidPortsDeadlinesAndMismatchedHostFilter()
+    {
+        DeploymentOptions options = ValidOptions() with
+        {
+            PublicUdpPort = 0,
+            DrainDeadlineSeconds = 31,
+            MinimumDrainSeconds = 6,
+        };
+
+        IReadOnlyList<string> errors = options.ValidateProduction(
+            new AbuseProtectionOptions { TrustedProxyAddresses = ["192.0.2.10"] },
+            "different.finalfactory.at");
+
+        Assert.Contains(errors, error => error.Contains("PublicUdpPort", StringComparison.Ordinal));
+        Assert.Contains(errors, error => error.Contains("DrainDeadlineSeconds", StringComparison.Ordinal));
+        Assert.Contains(errors, error => error.Contains("MinimumDrainSeconds", StringComparison.Ordinal));
+        Assert.Contains(errors, error => error.Contains("exact host", StringComparison.Ordinal));
+    }
+
+    private static DeploymentOptions ValidOptions() => new()
+    {
+        PublicHttpBaseUrl = "https://rendezvous.finalfactory.at/",
+        PublicUdpHost = "rendezvous-udp.finalfactory.at",
+        PublicUdpPort = 9050,
+        DrainDeadlineSeconds = 10,
+        MinimumDrainSeconds = 1,
+        SingleActiveInstance = true,
+    };
+}

tests/FinalFactory.Rendezvous.Tests/Deployment/GracefulDrainServiceTests.cs

@@ -0,0 +1,149 @@
+using System.Diagnostics;
+using FinalFactory.Rendezvous.Server.Deployment;
+using FinalFactory.Rendezvous.Server.State;
+using FinalFactory.Rendezvous.Tests.State;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+
+namespace FinalFactory.Rendezvous.Tests.Deployment;
+
+public sealed class GracefulDrainServiceTests
+{
+    [Fact]
+    public async Task ShutdownRejectsNewWorkAndClearsStateAfterBoundedAttemptDeadline()
+    {
+        EphemeralStoreOptions stateOptions = new()
+        {
+            GracefulDrainLifetime = TimeSpan.FromSeconds(1),
+        };
+        EphemeralStateFixture fixture = new(stateOptions);
+        StoredListing listing = fixture.CreateVisibleListing(out _);
+        StoreResult<StoredJoinAttempt> attempt = fixture.Store.CreateJoinAttempt(
+            fixture.AttemptCommand(listing));
+        Assert.True(attempt.Succeeded);
+        using FakeApplicationLifetime lifetime = new();
+        using GracefulDrainService service = CreateService(fixture.Store, lifetime);
+        await service.StartAsync(CancellationToken.None);
+
+        Task stopping = Task.Run(lifetime.StopApplication);
+        await WaitUntilAsync(() => fixture.Store.IsDraining, TimeSpan.FromSeconds(1));
+        StoreResult<StoredListing> rejected = fixture.Store.CreateListing(fixture.ListingCommand());
+        long sweepsAfterAdmissionCheck = fixture.Store.MaintenanceSweepCount;
+        Stopwatch elapsed = Stopwatch.StartNew();
+        await stopping;
+        await service.StopAsync(CancellationToken.None);
+
+        Assert.Equal(StoreResultCode.Draining, rejected.Code);
+        Assert.Equal(sweepsAfterAdmissionCheck, fixture.Store.MaintenanceSweepCount);
+        Assert.InRange(elapsed.Elapsed, TimeSpan.FromMilliseconds(850), TimeSpan.FromSeconds(2));
+        Assert.False(fixture.Store.IsAvailable);
+        Assert.Equal(0, fixture.Store.GetSnapshot().ActiveJoinAttempts);
+        Assert.Equal(0, fixture.Store.GetSnapshot().ActiveListings);
+    }
+
+    [Fact]
+    public async Task ShutdownWithoutAttemptsStopsAfterTheConfiguredMinimumOnly()
+    {
+        EphemeralStateFixture fixture = new(new EphemeralStoreOptions
+        {
+            GracefulDrainLifetime = TimeSpan.FromSeconds(2),
+        });
+        fixture.CreateVisibleListing(out _);
+        using FakeApplicationLifetime lifetime = new();
+        DeploymentOptions options = new()
+        {
+            DrainDeadlineSeconds = 2,
+            MinimumDrainSeconds = 0,
+        };
+        using GracefulDrainService service = new(
+            fixture.Store,
+            lifetime,
+            Options.Create(options),
+            NullLogger<GracefulDrainService>.Instance);
+        await service.StartAsync(CancellationToken.None);
+
+        Stopwatch elapsed = Stopwatch.StartNew();
+        await service.StopAsync(CancellationToken.None);
+
+        Assert.True(elapsed.Elapsed < TimeSpan.FromMilliseconds(500));
+        Assert.False(fixture.Store.IsAvailable);
+        Assert.Equal(0, fixture.Store.GetSnapshot().ActiveListings);
+    }
+
+    [Fact]
+    public async Task ShutdownStopsWhenTheLastAttemptExpiresWithoutAFullStateSweep()
+    {
+        EphemeralStateFixture fixture = new(new EphemeralStoreOptions
+        {
+            JoinAttemptLifetime = TimeSpan.FromMilliseconds(100),
+            ConnectionTicketLifetime = TimeSpan.FromMilliseconds(50),
+            GracefulDrainLifetime = TimeSpan.FromSeconds(2),
+        });
+        StoredListing listing = fixture.CreateVisibleListing(out _);
+        Assert.True(fixture.Store.CreateJoinAttempt(fixture.AttemptCommand(listing)).Succeeded);
+        using FakeApplicationLifetime lifetime = new();
+        using GracefulDrainService service = new(
+            fixture.Store,
+            lifetime,
+            Options.Create(new DeploymentOptions
+            {
+                DrainDeadlineSeconds = 2,
+                MinimumDrainSeconds = 0,
+            }),
+            NullLogger<GracefulDrainService>.Instance);
+        await service.StartAsync(CancellationToken.None);
+
+        Task stopping = Task.Run(lifetime.StopApplication);
+        await WaitUntilAsync(() => fixture.Store.IsDraining, TimeSpan.FromSeconds(1));
+        long sweepsBeforeExpiry = fixture.Store.MaintenanceSweepCount;
+        fixture.Clock.Advance(TimeSpan.FromMilliseconds(150));
+        using CancellationTokenSource timeout = new(TimeSpan.FromSeconds(1));
+        await stopping.WaitAsync(timeout.Token);
+
+        Assert.Equal(sweepsBeforeExpiry, fixture.Store.MaintenanceSweepCount);
+        Assert.False(fixture.Store.IsAvailable);
+    }
+
+    private static GracefulDrainService CreateService(
+        InMemoryEphemeralRendezvousStore store,
+        IHostApplicationLifetime lifetime) => new(
+            store,
+            lifetime,
+            Options.Create(new DeploymentOptions
+            {
+                DrainDeadlineSeconds = 1,
+                MinimumDrainSeconds = 0,
+            }),
+            NullLogger<GracefulDrainService>.Instance);
+
+    private static async Task WaitUntilAsync(Func<bool> predicate, TimeSpan timeout)
+    {
+        Stopwatch elapsed = Stopwatch.StartNew();
+        while (!predicate())
+        {
+            Assert.True(elapsed.Elapsed < timeout, "The service did not enter drain in time.");
+            await Task.Delay(10);
+        }
+    }
+
+    private sealed class FakeApplicationLifetime : IHostApplicationLifetime, IDisposable
+    {
+        private readonly CancellationTokenSource _started = new();
+        private readonly CancellationTokenSource _stopping = new();
+        private readonly CancellationTokenSource _stopped = new();
+
+        public CancellationToken ApplicationStarted => _started.Token;
+        public CancellationToken ApplicationStopping => _stopping.Token;
+        public CancellationToken ApplicationStopped => _stopped.Token;
+
+        public void StopApplication() => _stopping.Cancel();
+
+        public void Dispose()
+        {
+            _started.Dispose();
+            _stopping.Dispose();
+            _stopped.Dispose();
+        }
+    }
+}

tests/FinalFactory.Rendezvous.Tests/Deployment/ProductionProcessTests.cs

@@ -0,0 +1,458 @@
+using System.Diagnostics;
+using System.Net;
+using System.Net.Sockets;
+using System.Security.Cryptography;
+
+namespace FinalFactory.Rendezvous.Tests.Deployment;
+
+public sealed class ProductionProcessTests
+{
+    [Fact]
+    public async Task SigtermDrainsThenReleasesHttpAndUdpSockets()
+    {
+        if (!OperatingSystem.IsLinux())
+        {
+            return;
+        }
+
+        int httpPort = ReserveTcpPort();
+        int udpPort = ReserveUdpPort();
+        string secretPath = Path.Combine(
+            Path.GetTempPath(),
+            $"rendezvous-process-secret-{Guid.NewGuid():N}");
+        await File.WriteAllBytesAsync(secretPath, RandomNumberGenerator.GetBytes(32));
+        Process? process = null;
+        try
+        {
+            ProcessStartInfo startInfo = CreateStartInfo(httpPort, udpPort, secretPath);
+            process = Process.Start(startInfo)
+                ?? throw new InvalidOperationException("The production server process did not start.");
+            Task<string> standardOutput = process.StandardOutput.ReadToEndAsync();
+            Task<string> standardError = process.StandardError.ReadToEndAsync();
+
+            await WaitForReadyAsync(httpPort, process, TimeSpan.FromSeconds(10));
+            AssertUdpPortIsBound(udpPort);
+
+            Stopwatch shutdown = Stopwatch.StartNew();
+            ProcessStartInfo signalInfo = new()
+            {
+                FileName = "/bin/kill",
+                UseShellExecute = false,
+                ArgumentList =
+                {
+                    "-TERM",
+                    process.Id.ToString(System.Globalization.CultureInfo.InvariantCulture),
+                },
+            };
+            using (Process signal = Process.Start(signalInfo)
+                   ?? throw new InvalidOperationException("Could not send SIGTERM."))
+            {
+                await signal.WaitForExitAsync();
+                Assert.Equal(0, signal.ExitCode);
+            }
+
+            using CancellationTokenSource timeout = new(TimeSpan.FromSeconds(6));
+            await process.WaitForExitAsync(timeout.Token);
+            string output = await standardOutput;
+            string error = await standardError;
+            Assert.True(
+                process.ExitCode == 0,
+                $"Server exited with {process.ExitCode}. stdout: {output} stderr: {error}");
+            Assert.InRange(shutdown.Elapsed, TimeSpan.FromMilliseconds(700), TimeSpan.FromSeconds(5));
+            AssertTcpPortIsReleased(httpPort);
+            AssertUdpPortIsReleased(udpPort);
+        }
+        finally
+        {
+            if (process is not null)
+            {
+                if (!process.HasExited)
+                {
+                    process.Kill(entireProcessTree: true);
+                    await process.WaitForExitAsync();
+                }
+
+                process.Dispose();
+            }
+
+            File.Delete(secretPath);
+        }
+    }
+
+    [Fact]
+    public async Task DocumentedSmokeScriptReachesHttpAndAuthenticatedUdpFlow()
+    {
+        if (!OperatingSystem.IsLinux())
+        {
+            return;
+        }
+
+        string root = RepositoryRoot();
+        int httpPort = ReserveTcpPort();
+        int udpPort = ReserveUdpPort();
+        string secretPath = Path.Combine(
+            Path.GetTempPath(),
+            $"rendezvous-smoke-secret-{Guid.NewGuid():N}");
+        await File.WriteAllBytesAsync(secretPath, RandomNumberGenerator.GetBytes(32));
+        Process? server = null;
+        Process? smoke = null;
+        try
+        {
+            DateTimeOffset now = DateTimeOffset.UtcNow;
+            string assembly = typeof(Program).Assembly.Location;
+            ProcessStartInfo serverInfo = new()
+            {
+                FileName = "dotnet",
+                WorkingDirectory = root,
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
+                UseShellExecute = false,
+                ArgumentList =
+                {
+                    assembly,
+                    "--contentRoot", Path.Combine(root, "deploy", "compose"),
+                    "--Rendezvous:Provisioning:SigningKeys:0:SecretReference", $"file:{secretPath}",
+                    "--Rendezvous:Provisioning:SigningKeys:0:NotBefore", now.AddHours(-1).ToString("O"),
+                    "--Rendezvous:Provisioning:SigningKeys:0:SignUntil", now.AddHours(1).ToString("O"),
+                    "--Rendezvous:Provisioning:SigningKeys:0:VerifyUntil", now.AddHours(2).ToString("O"),
+                    "--Rendezvous:Udp:Port", udpPort.ToString(System.Globalization.CultureInfo.InvariantCulture),
+                    "--Rendezvous:Deployment:PublicUdpPort", udpPort.ToString(System.Globalization.CultureInfo.InvariantCulture),
+                },
+            };
+            serverInfo.Environment["ASPNETCORE_ENVIRONMENT"] = "Production";
+            serverInfo.Environment["ASPNETCORE_URLS"] = $"http://127.0.0.1:{httpPort}";
+            server = Process.Start(serverInfo)
+                ?? throw new InvalidOperationException("The smoke server process did not start.");
+            Task<string> serverOutput = server.StandardOutput.ReadToEndAsync();
+            Task<string> serverError = server.StandardError.ReadToEndAsync();
+            await WaitForReadyAsync(httpPort, server, TimeSpan.FromSeconds(10));
+
+            ProcessStartInfo smokeInfo = new()
+            {
+                FileName = Path.Combine(root, "scripts", "smoke-deployment.sh"),
+                WorkingDirectory = root,
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
+                UseShellExecute = false,
+            };
+            smokeInfo.Environment.Remove("RENDEZVOUS_PUBLISHER_CREDENTIAL");
+            smokeInfo.Environment["RENDEZVOUS_SMOKE_HTTP_URL"] = $"http://127.0.0.1:{httpPort}/";
+            smokeInfo.Environment["RENDEZVOUS_SMOKE_UDP_ENDPOINT"] = $"127.0.0.1:{udpPort}";
+            smokeInfo.Environment["RENDEZVOUS_SMOKE_LOCAL_KEY"] = secretPath;
+            smokeInfo.Environment["RENDEZVOUS_SMOKE_TIMEOUT_SECONDS"] = "15";
+            smokeInfo.Environment["RENDEZVOUS_SMOKE_CONFIGURATION"] = BuildConfiguration();
+            smoke = Process.Start(smokeInfo)
+                ?? throw new InvalidOperationException("The deployment smoke process did not start.");
+            Task<string> smokeOutput = smoke.StandardOutput.ReadToEndAsync();
+            Task<string> smokeError = smoke.StandardError.ReadToEndAsync();
+            using (CancellationTokenSource timeout = new(TimeSpan.FromSeconds(25)))
+            {
+                await smoke.WaitForExitAsync(timeout.Token);
+            }
+
+            string output = await smokeOutput;
+            string error = await smokeError;
+            Assert.True(
+                smoke.ExitCode == 0,
+                $"Smoke exited with {smoke.ExitCode}. stdout: {output} stderr: {error}");
+            Assert.Contains("deployment smoke passed", output, StringComparison.OrdinalIgnoreCase);
+            Assert.DoesNotContain("rv1.", output, StringComparison.Ordinal);
+            Assert.DoesNotContain("rv1.", error, StringComparison.Ordinal);
+
+            await SendSigtermAsync(server);
+            using CancellationTokenSource shutdownTimeout = new(TimeSpan.FromSeconds(6));
+            await server.WaitForExitAsync(shutdownTimeout.Token);
+            string finalServerOutput = await serverOutput;
+            string finalServerError = await serverError;
+            Assert.True(
+                server.ExitCode == 0,
+                $"Smoke server failed. stdout: {finalServerOutput} stderr: {finalServerError}");
+        }
+        finally
+        {
+            await StopProcessTreeAsync(smoke);
+            if (server is not null)
+            {
+                await StopProcessTreeAsync(server);
+            }
+
+            File.Delete(secretPath);
+        }
+    }
+
+    [Theory]
+    [InlineData("missing-deployment", "PublicHttpBaseUrl")]
+    [InlineData("wildcard-host", "AllowedHosts")]
+    [InlineData("reserved-endpoint", "public DNS name or address")]
+    [InlineData("missing-key", "process-test-key")]
+    public async Task UnsafeProductionConfigurationFailsBeforeBinding(
+        string scenario,
+        string expectedDiagnostic)
+    {
+        if (!OperatingSystem.IsLinux())
+        {
+            return;
+        }
+
+        int httpPort = ReserveTcpPort();
+        int udpPort = ReserveUdpPort();
+        string secretPath = Path.Combine(
+            Path.GetTempPath(),
+            $"rendezvous-rejected-secret-{Guid.NewGuid():N}");
+        await File.WriteAllBytesAsync(secretPath, RandomNumberGenerator.GetBytes(32));
+        Process? process = null;
+        try
+        {
+            ProcessStartInfo startInfo = scenario == "missing-deployment"
+                ? CreateBareProductionStartInfo(httpPort)
+                : CreateStartInfo(httpPort, udpPort, secretPath);
+            if (scenario == "wildcard-host")
+            {
+                startInfo.Environment["AllowedHosts"] = "*";
+            }
+            else if (scenario == "reserved-endpoint")
+            {
+                startInfo.Environment["Rendezvous__Deployment__AllowPrivatePublicEndpoints"] = "false";
+                startInfo.Environment["Rendezvous__Deployment__PublicHttpBaseUrl"] = "https://192.0.2.1/";
+                startInfo.Environment["Rendezvous__Deployment__PublicUdpHost"] = "203.0.113.1";
+                startInfo.Environment["AllowedHosts"] = "192.0.2.1";
+            }
+            else if (scenario == "missing-key")
+            {
+                File.Delete(secretPath);
+            }
+
+            process = Process.Start(startInfo)
+                ?? throw new InvalidOperationException("The rejected production process did not start.");
+            Task<string> standardOutput = process.StandardOutput.ReadToEndAsync();
+            Task<string> standardError = process.StandardError.ReadToEndAsync();
+            using CancellationTokenSource timeout = new(TimeSpan.FromSeconds(6));
+            await process.WaitForExitAsync(timeout.Token);
+            string diagnostic = $"{await standardOutput}\n{await standardError}";
+
+            Assert.NotEqual(0, process.ExitCode);
+            Assert.Contains(expectedDiagnostic, diagnostic, StringComparison.OrdinalIgnoreCase);
+            AssertTcpPortIsReleased(httpPort);
+            AssertUdpPortIsReleased(udpPort);
+        }
+        finally
+        {
+            await StopProcessTreeAsync(process);
+            File.Delete(secretPath);
+        }
+    }
+
+    private static ProcessStartInfo CreateStartInfo(int httpPort, int udpPort, string secretPath)
+    {
+        string assembly = typeof(Program).Assembly.Location;
+        ProcessStartInfo info = new()
+        {
+            FileName = "dotnet",
+            WorkingDirectory = Path.GetDirectoryName(assembly)!,
+            RedirectStandardOutput = true,
+            RedirectStandardError = true,
+            UseShellExecute = false,
+        };
+        info.ArgumentList.Add(assembly);
+        Dictionary<string, string> settings = new(StringComparer.Ordinal)
+        {
+            ["ASPNETCORE_ENVIRONMENT"] = "Production",
+            ["ASPNETCORE_URLS"] = $"http://127.0.0.1:{httpPort}",
+            ["AllowedHosts"] = "127.0.0.1",
+            ["Rendezvous__Deployment__PublicHttpBaseUrl"] = "https://127.0.0.1/",
+            ["Rendezvous__Deployment__PublicUdpHost"] = "127.0.0.1",
+            ["Rendezvous__Deployment__PublicUdpPort"] = udpPort.ToString(System.Globalization.CultureInfo.InvariantCulture),
+            ["Rendezvous__Deployment__DrainDeadlineSeconds"] = "3",
+            ["Rendezvous__Deployment__MinimumDrainSeconds"] = "1",
+            ["Rendezvous__Deployment__SingleActiveInstance"] = "true",
+            ["Rendezvous__Deployment__AllowPrivatePublicEndpoints"] = "true",
+            ["Rendezvous__Udp__ListenAddress"] = "127.0.0.1",
+            ["Rendezvous__Udp__Port"] = udpPort.ToString(System.Globalization.CultureInfo.InvariantCulture),
+            ["Rendezvous__AbuseProtection__TrustedProxyAddresses__0"] = "127.0.0.1",
+            ["Rendezvous__Provisioning__Issuer"] = "rendezvous-process-test",
+            ["Rendezvous__Provisioning__Audience"] = "rendezvous-service",
+            ["Rendezvous__Provisioning__ClockSkewSeconds"] = "30",
+            ["Rendezvous__Provisioning__SigningKeys__0__KeyId"] = "process-test-key",
+            ["Rendezvous__Provisioning__SigningKeys__0__SecretReference"] = $"file:{secretPath}",
+            ["Rendezvous__Provisioning__SigningKeys__0__CredentialKinds__0"] = "DedicatedPublisher",
+            ["Rendezvous__Provisioning__SigningKeys__0__GameId"] = "space-game",
+            ["Rendezvous__Provisioning__SigningKeys__0__EnvironmentId"] = "process-test",
+            ["Rendezvous__Provisioning__SigningKeys__0__NotBefore"] = DateTimeOffset.UtcNow.AddHours(-1).ToString("O"),
+            ["Rendezvous__Provisioning__SigningKeys__0__SignUntil"] = DateTimeOffset.UtcNow.AddDays(1).ToString("O"),
+            ["Rendezvous__Provisioning__SigningKeys__0__VerifyUntil"] = DateTimeOffset.UtcNow.AddDays(2).ToString("O"),
+            ["Rendezvous__Provisioning__Games__0__GameId"] = "space-game",
+            ["Rendezvous__Provisioning__Games__0__EnvironmentId"] = "process-test",
+            ["Rendezvous__Provisioning__Games__0__Enabled"] = "true",
+            ["Rendezvous__Provisioning__Games__0__ProtocolVersions__0"] = "1",
+            ["Rendezvous__Provisioning__Games__0__Regions__0"] = "local",
+            ["Rendezvous__Provisioning__Games__0__VisibilityModes__0"] = "Public",
+            ["Rendezvous__Provisioning__Games__0__PublisherTrustModes__0"] = "ManagedDedicated",
+            ["Rendezvous__Provisioning__Games__0__MetadataMaxBytes"] = "512",
+            ["Rendezvous__Provisioning__Games__0__MetadataMaxKeys"] = "0",
+            ["Rendezvous__Provisioning__Games__0__MaxListingsPerPrincipal"] = "10",
+            ["Rendezvous__Provisioning__Games__0__MaxAnonymousListingsPerAddress"] = "0",
+            ["Rendezvous__Provisioning__Games__0__MaxActiveJoinAttempts"] = "100",
+            ["Rendezvous__Provisioning__Games__0__FallbackPolicy"] = "Disabled",
+        };
+        foreach ((string key, string value) in settings)
+        {
+            info.Environment[key] = value;
+        }
+
+        return info;
+    }
+
+    private static ProcessStartInfo CreateBareProductionStartInfo(int httpPort)
+    {
+        string assembly = typeof(Program).Assembly.Location;
+        ProcessStartInfo info = new()
+        {
+            FileName = "dotnet",
+            WorkingDirectory = Path.GetDirectoryName(assembly)!,
+            RedirectStandardOutput = true,
+            RedirectStandardError = true,
+            UseShellExecute = false,
+        };
+        info.ArgumentList.Add(assembly);
+        foreach (string key in info.Environment.Keys
+                     .Where(static key => key.StartsWith("Rendezvous__", StringComparison.OrdinalIgnoreCase))
+                     .ToArray())
+        {
+            info.Environment.Remove(key);
+        }
+
+        info.Environment["ASPNETCORE_ENVIRONMENT"] = "Production";
+        info.Environment["ASPNETCORE_URLS"] = $"http://127.0.0.1:{httpPort}";
+        info.Environment["AllowedHosts"] = "*";
+        return info;
+    }
+
+    private static async Task StopProcessTreeAsync(Process? process)
+    {
+        if (process is null)
+        {
+            return;
+        }
+
+        try
+        {
+            if (!process.HasExited)
+            {
+                process.Kill(entireProcessTree: true);
+                using CancellationTokenSource timeout = new(TimeSpan.FromSeconds(3));
+                await process.WaitForExitAsync(timeout.Token);
+            }
+        }
+        finally
+        {
+            process.Dispose();
+        }
+    }
+
+    private static async Task SendSigtermAsync(Process process)
+    {
+        ProcessStartInfo signalInfo = new()
+        {
+            FileName = "/bin/kill",
+            UseShellExecute = false,
+            ArgumentList =
+            {
+                "-TERM",
+                process.Id.ToString(System.Globalization.CultureInfo.InvariantCulture),
+            },
+        };
+        using Process signal = Process.Start(signalInfo)
+            ?? throw new InvalidOperationException("Could not send SIGTERM.");
+        await signal.WaitForExitAsync();
+        Assert.Equal(0, signal.ExitCode);
+    }
+
+    private static string BuildConfiguration()
+    {
+        string path = typeof(ProductionProcessTests).Assembly.Location;
+        return path.Contains(
+            $"{Path.DirectorySeparatorChar}Release{Path.DirectorySeparatorChar}",
+            StringComparison.Ordinal)
+            ? "Release"
+            : "Debug";
+    }
+
+    private static string RepositoryRoot()
+    {
+        DirectoryInfo? directory = new(AppContext.BaseDirectory);
+        while (directory is not null && !File.Exists(Path.Combine(directory.FullName, "Rendezvous.slnx")))
+        {
+            directory = directory.Parent;
+        }
+
+        return directory?.FullName
+            ?? throw new InvalidOperationException("Could not locate the repository root.");
+    }
+
+    private static async Task WaitForReadyAsync(int port, Process process, TimeSpan timeout)
+    {
+        using HttpClient client = new() { Timeout = TimeSpan.FromMilliseconds(500) };
+        Stopwatch elapsed = Stopwatch.StartNew();
+        while (elapsed.Elapsed < timeout)
+        {
+            if (process.HasExited)
+            {
+                throw new InvalidOperationException("The production server exited before readiness.");
+            }
+
+            try
+            {
+                using HttpResponseMessage response = await client.GetAsync(
+                    $"http://127.0.0.1:{port}/health/ready");
+                if (response.StatusCode == HttpStatusCode.OK)
+                {
+                    return;
+                }
+            }
+            catch (HttpRequestException)
+            {
+            }
+            catch (TaskCanceledException)
+            {
+            }
+
+            await Task.Delay(50);
+        }
+
+        throw new TimeoutException("The production server did not become ready.");
+    }
+
+    private static int ReserveTcpPort()
+    {
+        TcpListener listener = new(IPAddress.Loopback, 0);
+        listener.Start();
+        int port = ((IPEndPoint)listener.LocalEndpoint).Port;
+        listener.Stop();
+        return port;
+    }
+
+    private static int ReserveUdpPort()
+    {
+        using UdpClient client = new(new IPEndPoint(IPAddress.Loopback, 0));
+        return ((IPEndPoint)client.Client.LocalEndPoint!).Port;
+    }
+
+    private static void AssertUdpPortIsBound(int port)
+    {
+        using Socket socket = new(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
+        Assert.Throws<SocketException>(() => socket.Bind(new IPEndPoint(IPAddress.Loopback, port)));
+    }
+
+    private static void AssertTcpPortIsReleased(int port)
+    {
+        TcpListener listener = new(IPAddress.Loopback, port);
+        listener.Start();
+        listener.Stop();
+    }
+
+    private static void AssertUdpPortIsReleased(int port)
+    {
+        using Socket socket = new(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
+        socket.Bind(new IPEndPoint(IPAddress.Loopback, port));
+    }
+}

tests/FinalFactory.Rendezvous.Tests/JoinAttempts/JoinAttemptHttpEndpointTests.cs

@@ -2,6 +2,7 @@ using System.Net;
 using System.Net.Http.Json;
 using FinalFactory.Rendezvous.Client;
 using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Abuse;
 using FinalFactory.Rendezvous.Server.Browser;
 using FinalFactory.Rendezvous.Server.ConnectionOutcomes;
 using FinalFactory.Rendezvous.Server.Http;
@@ -304,6 +305,8 @@ public sealed class JoinAttemptHttpEndpointTests
                 options.ThrowOnBadRequest = true);
             builder.Services.AddProblemDetails();
             builder.Services.AddExceptionHandler<RendezvousExceptionHandler>();
+            builder.Services.AddOptions<AbuseProtectionOptions>();
+            builder.Services.AddSingleton<AbuseProtectionService>();
             builder.Services.AddSingleton(provisioning);
             builder.Services.AddSingleton(provisioning.Policies);
             builder.Services.AddSingleton(provisioning.Credentials);
@@ -324,6 +327,7 @@ public sealed class JoinAttemptHttpEndpointTests
 
             WebApplication app = builder.Build();
             app.UseExceptionHandler();
+            app.UseMiddleware<HttpAbuseProtectionMiddleware>();
             app.MapRendezvousContractEndpoints();
             await app.StartAsync();
             IServer server = app.Services.GetRequiredService<IServer>();

tests/FinalFactory.Rendezvous.Tests/Observability/ObservabilityTests.cs

@@ -0,0 +1,253 @@
+using System.Collections.Concurrent;
+using System.Diagnostics;
+using System.Diagnostics.Metrics;
+using System.Net;
+using FinalFactory.Rendezvous.Server.Observability;
+using FinalFactory.Rendezvous.Server.State;
+using FinalFactory.Rendezvous.Server.Transport;
+using FinalFactory.Rendezvous.Tests.State;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+namespace FinalFactory.Rendezvous.Tests.Observability;
+
+[CollectionDefinition(RendezvousTelemetryIsolation.Name, DisableParallelization = true)]
+public sealed class RendezvousTelemetryIsolation
+{
+    public const string Name = "Rendezvous telemetry";
+}
+
+[Collection(RendezvousTelemetryIsolation.Name)]
+public sealed class ObservabilityTests
+{
+    private static readonly HashSet<string> AllowedTagKeys =
+    [
+        "operation",
+        "status_code",
+        "result",
+        "transport",
+        "partition",
+        "action",
+        "outcome",
+        "elapsed_bucket",
+    ];
+
+    [Fact]
+    public void MetricsAndTracesUseBoundedDimensionsWithoutSensitiveValues()
+    {
+        EphemeralStateFixture fixture = new();
+        using RendezvousTelemetry telemetry = new(fixture.Store);
+        List<Measurement> measurements = [];
+        using MeterListener meterListener = new();
+        meterListener.InstrumentPublished = (instrument, listener) =>
+        {
+            if (instrument.Meter.Name == RendezvousTelemetry.MeterName)
+            {
+                listener.EnableMeasurementEvents(instrument);
+            }
+        };
+        meterListener.SetMeasurementEventCallback<long>((instrument, value, tags, _) =>
+            measurements.Add(new(instrument.Name, value, Tags(tags))));
+        meterListener.SetMeasurementEventCallback<int>((instrument, value, tags, _) =>
+            measurements.Add(new(instrument.Name, value, Tags(tags))));
+        meterListener.SetMeasurementEventCallback<double>((instrument, value, tags, _) =>
+            measurements.Add(new(instrument.Name, value, Tags(tags))));
+        meterListener.Start();
+
+        Activity? observed = null;
+        List<string> activityData = [];
+        using ActivityListener activityListener = new()
+        {
+            ShouldListenTo = source => source.Name == RendezvousTelemetry.ActivitySourceName,
+            Sample = static (ref ActivityCreationOptions<ActivityContext> _) =>
+                ActivitySamplingResult.AllData,
+            ActivityStopped = activity =>
+            {
+                observed = activity;
+                activityData.Add(activity.DisplayName);
+                activityData.AddRange(activity.TagObjects.Select(static tag => $"{tag.Key}={tag.Value}"));
+            },
+        };
+        ActivitySource.AddActivityListener(activityListener);
+
+        const string secret = "secret-player-token-canary";
+        using (telemetry.StartActivity("HTTP GetOperatorStatus", ActivityKind.Server))
+        {
+            telemetry.RecordHttp("GetOperatorStatus", 200, 3.5);
+            telemetry.RecordUdp("frozen", "Introduced", 1.25);
+            telemetry.RecordLimiterDrop("udp", "rate-or-concurrency");
+            telemetry.RecordAudit("revoke-listing", "succeeded");
+            telemetry.RecordConnectionOutcome("Connected", "UnderOneSecond");
+            telemetry.RecordOperatorAuthentication("accepted");
+            telemetry.RecordPairingLatency(12.5);
+        }
+        NatMediationProcessor processor = new(null!, null!, null!, telemetry: telemetry);
+        Assert.Equal(
+            NatMediationResult.Dropped,
+            processor.ProcessRequest(
+                new IPEndPoint(IPAddress.Parse("10.0.0.8"), 9000),
+                new IPEndPoint(IPAddress.Parse("203.0.113.8"), 50000),
+                secret,
+                NoopIntroductionSink.Instance));
+
+        meterListener.RecordObservableInstruments();
+        Assert.NotNull(observed);
+        string flattened = string.Join('|', measurements.Select(static item => item.ToString()));
+        Assert.DoesNotContain(secret, flattened, StringComparison.Ordinal);
+        Assert.DoesNotContain(secret, string.Join('|', activityData), StringComparison.Ordinal);
+        Assert.Contains(measurements, static item => item.Name == "rendezvous.http.requests");
+        Assert.Contains(measurements, static item => item.Name == "rendezvous.udp.results");
+        Assert.Contains(measurements, static item => item.Name == "rendezvous.limiter.drops");
+        Assert.Contains(measurements, static item => item.Name == "rendezvous.queue.depth");
+        Assert.Contains(measurements, static item => item.Name == "rendezvous.store.active_leases");
+        Assert.Contains(measurements, static item => item.Name == "rendezvous.store.expiry_churn");
+        Assert.Contains(measurements, static item => item.Name == "rendezvous.pairing.latency");
+        Assert.All(measurements.SelectMany(static item => item.Tags), static tag =>
+            Assert.Contains(tag.Key, AllowedTagKeys));
+    }
+
+    [Fact]
+    public void MetricScrapeExpiresIdleStateAndReportsExpiryChurn()
+    {
+        EphemeralStateFixture fixture = new();
+        Assert.True(fixture.Store.CreateListing(fixture.ListingCommand()).Succeeded);
+        using RendezvousTelemetry telemetry = new(fixture.Store);
+        List<Measurement> measurements = [];
+        using MeterListener listener = new();
+        listener.InstrumentPublished = (instrument, meterListener) =>
+        {
+            if (instrument.Meter.Name == RendezvousTelemetry.MeterName)
+            {
+                meterListener.EnableMeasurementEvents(instrument);
+            }
+        };
+        listener.SetMeasurementEventCallback<long>((instrument, value, tags, _) =>
+            measurements.Add(new(instrument.Name, value, Tags(tags))));
+        listener.SetMeasurementEventCallback<int>((instrument, value, tags, _) =>
+            measurements.Add(new(instrument.Name, value, Tags(tags))));
+        listener.Start();
+
+        listener.RecordObservableInstruments();
+        Assert.Equal(
+            1,
+            Assert.Single(measurements, static item => item.Name == "rendezvous.store.active_leases").Value);
+
+        fixture.Clock.Advance(TimeSpan.FromSeconds(61));
+        measurements.Clear();
+        listener.RecordObservableInstruments();
+        Assert.Equal(
+            0,
+            Assert.Single(measurements, static item => item.Name == "rendezvous.store.active_leases").Value);
+        Assert.True(Assert.Single(
+            measurements,
+            static item => item.Name == "rendezvous.store.expiry_churn").Value >= 1);
+    }
+
+    [Fact]
+    public void AuditTrailFingerprintsIdentifiersEnforcesRetentionAndBoundsCapacity()
+    {
+        EphemeralStateFixture fixture = new();
+        using RendezvousTelemetry telemetry = new(fixture.Store);
+        CapturingLogger<AuditTrail> logger = new();
+        ManualTimeProvider time = new(new DateTimeOffset(2026, 7, 16, 0, 0, 0, TimeSpan.Zero));
+        AuditTrail audit = new(
+            Options.Create(new AuditOptions { MaxEntries = 100, RetentionDays = 1 }),
+            logger,
+            telemetry,
+            time);
+        const string actor = "operator-secret-subject";
+        const string target = "player-secret-subject";
+
+        for (int index = 0; index < 101; index++)
+        {
+            audit.Record(actor, "revoke-principal", "succeeded", "principal", target, "safe-correlation");
+        }
+
+        IReadOnlyList<AuditEntry> bounded = audit.GetEntriesForTests();
+        Assert.Equal(100, bounded.Count);
+        Assert.All(bounded, entry =>
+        {
+            Assert.DoesNotContain(actor, entry.ToString(), StringComparison.Ordinal);
+            Assert.DoesNotContain(target, entry.ToString(), StringComparison.Ordinal);
+            Assert.NotEqual(actor, entry.ActorFingerprint);
+            Assert.NotEqual(target, entry.TargetFingerprint);
+        });
+        Assert.DoesNotContain(actor, string.Join('|', logger.Messages), StringComparison.Ordinal);
+        Assert.DoesNotContain(target, string.Join('|', logger.Messages), StringComparison.Ordinal);
+
+        time.Advance(TimeSpan.FromDays(2));
+        Assert.Empty(audit.GetEntriesForTests());
+        Assert.Empty(audit.GetAggregateCounts());
+        audit.Record(actor, "inspect-status", "succeeded", "service", "rendezvous", "safe-correlation");
+        Assert.Single(audit.GetEntriesForTests());
+        Assert.Equal(1, audit.GetAggregateCounts()["inspect-status:succeeded"]);
+    }
+
+    private static KeyValuePair<string, object?>[] Tags(
+        ReadOnlySpan<KeyValuePair<string, object?>> tags) => tags.ToArray();
+
+    private sealed record Measurement(
+        string Name,
+        double Value,
+        KeyValuePair<string, object?>[] Tags);
+
+    private sealed class ManualTimeProvider(DateTimeOffset now) : TimeProvider
+    {
+        private DateTimeOffset _now = now;
+        public override DateTimeOffset GetUtcNow() => _now;
+        public void Advance(TimeSpan duration) => _now += duration;
+    }
+
+    private sealed class NoopIntroductionSink : INatIntroductionSink
+    {
+        public static NoopIntroductionSink Instance { get; } = new();
+        public void Introduce(NatIntroductionPlan plan)
+        {
+        }
+    }
+}
+
+internal sealed class CapturingLogger<T> : ILogger<T>
+{
+    public List<string> Messages { get; } = [];
+
+    public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
+    public bool IsEnabled(LogLevel logLevel) => true;
+
+    public void Log<TState>(
+        LogLevel logLevel,
+        EventId eventId,
+        TState state,
+        Exception? exception,
+        Func<TState, Exception?, string> formatter) => Messages.Add(formatter(state, exception));
+}
+
+internal sealed class CapturingLoggerProvider : ILoggerProvider
+{
+    public ConcurrentQueue<string> Messages { get; } = new();
+
+    public ILogger CreateLogger(string categoryName) => new Sink(Messages);
+
+    public void Dispose() => GC.SuppressFinalize(this);
+
+    private sealed class Sink(ConcurrentQueue<string> messages) : ILogger
+    {
+        public IDisposable BeginScope<TState>(TState state) where TState : notnull => Scope.Instance;
+        public bool IsEnabled(LogLevel logLevel) => true;
+
+        public void Log<TState>(
+            LogLevel logLevel,
+            EventId eventId,
+            TState state,
+            Exception? exception,
+            Func<TState, Exception?, string> formatter) => messages.Enqueue(formatter(state, exception));
+    }
+
+    private sealed class Scope : IDisposable
+    {
+        public static Scope Instance { get; } = new();
+        public void Dispose()
+        {
+        }
+    }
+}

tests/FinalFactory.Rendezvous.Tests/Operations/OperatorEndpointTests.cs

@@ -0,0 +1,519 @@
+using System.Diagnostics;
+using System.Diagnostics.Metrics;
+using System.Net;
+using System.Net.Http.Headers;
+using System.Net.Http.Json;
+using System.Text.Json;
+using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Abuse;
+using FinalFactory.Rendezvous.Server.Http;
+using FinalFactory.Rendezvous.Server.JoinAttempts;
+using FinalFactory.Rendezvous.Server.Observability;
+using FinalFactory.Rendezvous.Server.Operations;
+using FinalFactory.Rendezvous.Server.Provisioning;
+using FinalFactory.Rendezvous.Server.Sessions;
+using FinalFactory.Rendezvous.Server.State;
+using FinalFactory.Rendezvous.Server.Transport;
+using FinalFactory.Rendezvous.Tests.Observability;
+using FinalFactory.Rendezvous.Tests.Provisioning;
+using FinalFactory.Rendezvous.Tests.State;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Hosting.Server;
+using Microsoft.AspNetCore.Hosting.Server.Features;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+
+namespace FinalFactory.Rendezvous.Tests.Operations;
+
+[Collection(RendezvousTelemetryIsolation.Name)]
+public sealed class OperatorEndpointTests
+{
+    [Fact]
+    public async Task OperatorSurfaceSeparatesAuthenticationConfirmsActionsAndRedactsInspection()
+    {
+        await using OperatorTestHost host = await OperatorTestHost.StartAsync();
+        List<string> telemetryData = [];
+        using MeterListener meterListener = new();
+        meterListener.InstrumentPublished = (instrument, listener) =>
+        {
+            if (instrument.Meter.Name == RendezvousTelemetry.MeterName)
+            {
+                listener.EnableMeasurementEvents(instrument);
+            }
+        };
+        meterListener.SetMeasurementEventCallback<long>((instrument, value, tags, _) =>
+            CaptureMeasurement(telemetryData, instrument, value, tags));
+        meterListener.SetMeasurementEventCallback<int>((instrument, value, tags, _) =>
+            CaptureMeasurement(telemetryData, instrument, value, tags));
+        meterListener.SetMeasurementEventCallback<double>((instrument, value, tags, _) =>
+            CaptureMeasurement(telemetryData, instrument, value, tags));
+        meterListener.Start();
+        using ActivityListener activityListener = new()
+        {
+            ShouldListenTo = static source => source.Name == RendezvousTelemetry.ActivitySourceName,
+            Sample = static (ref ActivityCreationOptions<ActivityContext> _) =>
+                ActivitySamplingResult.AllData,
+            ActivityStopped = activity =>
+            {
+                telemetryData.Add(activity.DisplayName);
+                telemetryData.AddRange(activity.TagObjects.Select(static tag => $"{tag.Key}={tag.Value}"));
+            },
+        };
+        ActivitySource.AddActivityListener(activityListener);
+
+        using HttpResponseMessage liveBeforeDependencies = await host.Client.GetAsync("/health/live");
+        Assert.Equal(HttpStatusCode.OK, liveBeforeDependencies.StatusCode);
+        using HttpResponseMessage readyBeforeUdp = await host.Client.GetAsync("/health/ready");
+        Assert.Equal(HttpStatusCode.ServiceUnavailable, readyBeforeUdp.StatusCode);
+
+        using HttpResponseMessage unauthenticated = await host.Client.GetAsync("/v1/operator/status");
+        Assert.Equal(HttpStatusCode.Unauthorized, unauthenticated.StatusCode);
+        AuthenticationHeaderValue challenge = Assert.Single(
+            unauthenticated.Headers.WwwAuthenticate);
+        Assert.Equal("Bearer", challenge.Scheme);
+        Assert.Equal("realm=\"operator\"", challenge.Parameter);
+
+        using HttpResponseMessage publisher = await SendAsync(
+            host,
+            HttpMethod.Get,
+            "/v1/operator/status",
+            host.PublisherCredential);
+        Assert.Equal(HttpStatusCode.Unauthorized, publisher.StatusCode);
+
+        using HttpResponseMessage status = await SendAsync(
+            host,
+            HttpMethod.Get,
+            "/v1/operator/status",
+            host.ReadOnlyOperatorCredential);
+        Assert.Equal(HttpStatusCode.OK, status.StatusCode);
+        string statusJson = await status.Content.ReadAsStringAsync();
+        Assert.Contains("not-ready", statusJson, StringComparison.Ordinal);
+        Assert.DoesNotContain(host.OwnerCanary, statusJson, StringComparison.Ordinal);
+        Assert.DoesNotContain("203.0.113.25", statusJson, StringComparison.Ordinal);
+        Assert.DoesNotContain("metadata", statusJson, StringComparison.OrdinalIgnoreCase);
+        OperatorStatusResponse? operatorStatus = JsonSerializer.Deserialize<OperatorStatusResponse>(
+            statusJson,
+            ContractJson.Options);
+        Assert.Contains(operatorStatus!.Tenants, static tenant =>
+            tenant.GameId == "space-game"
+            && tenant.EnvironmentId == "production"
+            && tenant.Status == "enabled");
+        Assert.Contains(operatorStatus.SigningKeys, static key =>
+            key.KeyId == OperatorTestHost.OperatorKeyId
+            && key.Status == "signing"
+            && key.CredentialKinds.SequenceEqual(["Operator"]));
+
+        await host.StartUdpAsync();
+        using HttpResponseMessage readyAfterUdp = await host.Client.GetAsync("/health/ready");
+        Assert.Equal(HttpStatusCode.OK, readyAfterUdp.StatusCode);
+
+        using HttpResponseMessage exception = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/test/exception",
+            host.FullOperatorCredential);
+        Assert.Equal(HttpStatusCode.InternalServerError, exception.StatusCode);
+        using HttpResponseMessage saturatedPublic = await host.Client.GetAsync("/test/public");
+        Assert.Equal(HttpStatusCode.TooManyRequests, saturatedPublic.StatusCode);
+
+        using HttpResponseMessage forbidden = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/v1/operator/drain",
+            host.ReadOnlyOperatorCredential,
+            new BeginDrainRequest { Confirmation = "DRAIN" });
+        Assert.Equal(HttpStatusCode.Forbidden, forbidden.StatusCode);
+
+        SessionListingId listingId = host.CreateListing(host.OwnerCanary);
+        using HttpResponseMessage unconfirmedListing = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/v1/operator/listings/revoke",
+            host.FullOperatorCredential,
+            new RevokeListingRequest
+            {
+                ListingId = listingId.ToString(),
+                ConfirmListingId = Guid.NewGuid().ToString("D"),
+            });
+        Assert.Equal(HttpStatusCode.BadRequest, unconfirmedListing.StatusCode);
+        Assert.True(host.Store.GetListing(listingId, false).Succeeded);
+
+        using HttpResponseMessage revokedListing = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/v1/operator/listings/revoke",
+            host.FullOperatorCredential,
+            new RevokeListingRequest
+            {
+                ListingId = listingId.ToString(),
+                ConfirmListingId = listingId.ToString(),
+            });
+        Assert.Equal(HttpStatusCode.OK, revokedListing.StatusCode);
+        Assert.Equal(StoreResultCode.NotFound, host.Store.GetListing(listingId, false).Code);
+
+        const string principalCanary = "publisher-player-canary";
+        SessionListingId principalListing = host.CreateListing(principalCanary);
+        using HttpResponseMessage unconfirmedPrincipal = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/v1/operator/principals/revoke",
+            host.FullOperatorCredential,
+            new RevokePrincipalRequest
+            {
+                Subject = principalCanary,
+                ConfirmSubject = "different-subject",
+                LifetimeSeconds = 60,
+            });
+        Assert.Equal(HttpStatusCode.BadRequest, unconfirmedPrincipal.StatusCode);
+        Assert.True(host.Store.GetListing(principalListing, false).Succeeded);
+
+        using HttpResponseMessage revokedPrincipal = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/v1/operator/principals/revoke",
+            host.FullOperatorCredential,
+            new RevokePrincipalRequest
+            {
+                Subject = principalCanary,
+                ConfirmSubject = principalCanary,
+                LifetimeSeconds = 60,
+            });
+        Assert.Equal(HttpStatusCode.OK, revokedPrincipal.StatusCode);
+        OperatorActionResponse? principalResult = await revokedPrincipal.Content
+            .ReadFromJsonAsync<OperatorActionResponse>(ContractJson.Options);
+        Assert.Equal(1, principalResult!.AffectedResources);
+        Assert.Equal(StoreResultCode.NotFound, host.Store.GetListing(principalListing, false).Code);
+        StoreResult<StoredListing> blockedPublisher = host.CreateListingResult(
+            principalCanary,
+            out _);
+        Assert.Equal(StoreResultCode.Revoked, blockedPublisher.Code);
+
+        using HttpResponseMessage drain = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/v1/operator/drain",
+            host.FullOperatorCredential,
+            new BeginDrainRequest { Confirmation = "DRAIN" });
+        Assert.Equal(HttpStatusCode.OK, drain.StatusCode);
+        Assert.True(host.Store.IsDraining);
+        using HttpResponseMessage liveDuringDrain = await host.Client.GetAsync("/health/live");
+        Assert.Equal(HttpStatusCode.OK, liveDuringDrain.StatusCode);
+        using HttpResponseMessage readyDuringDrain = await host.Client.GetAsync("/health/ready");
+        Assert.Equal(HttpStatusCode.ServiceUnavailable, readyDuringDrain.StatusCode);
+
+        using HttpResponseMessage firstPublisherKeyRevocation = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/v1/operator/keys/revoke",
+            host.FullOperatorCredential,
+            new RevokeSigningKeyRequest { KeyId = "key-1", ConfirmKeyId = "key-1" });
+        Assert.Equal(HttpStatusCode.OK, firstPublisherKeyRevocation.StatusCode);
+        using HttpResponseMessage repeatedPublisherKeyRevocation = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/v1/operator/keys/revoke",
+            host.FullOperatorCredential,
+            new RevokeSigningKeyRequest { KeyId = "key-1", ConfirmKeyId = "key-1" });
+        Assert.Equal(HttpStatusCode.OK, repeatedPublisherKeyRevocation.StatusCode);
+
+        using HttpResponseMessage unconfirmedKey = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/v1/operator/keys/revoke",
+            host.FullOperatorCredential,
+            new RevokeSigningKeyRequest
+            {
+                KeyId = OperatorTestHost.OperatorKeyId,
+                ConfirmKeyId = "different-key",
+            });
+        Assert.Equal(HttpStatusCode.BadRequest, unconfirmedKey.StatusCode);
+
+        using HttpResponseMessage revokedKey = await SendAsync(
+            host,
+            HttpMethod.Post,
+            "/v1/operator/keys/revoke",
+            host.FullOperatorCredential,
+            new RevokeSigningKeyRequest
+            {
+                KeyId = OperatorTestHost.OperatorKeyId,
+                ConfirmKeyId = OperatorTestHost.OperatorKeyId,
+            });
+        Assert.Equal(HttpStatusCode.OK, revokedKey.StatusCode);
+        using HttpResponseMessage afterKeyRevocation = await SendAsync(
+            host,
+            HttpMethod.Get,
+            "/v1/operator/status",
+            host.FullOperatorCredential);
+        Assert.Equal(HttpStatusCode.Unauthorized, afterKeyRevocation.StatusCode);
+
+        string auditText = string.Join('|', host.Audit.GetEntriesForTests());
+        string logText = string.Join('|', host.AuditLogger.Messages.Concat(host.AllLogs.Messages));
+        Assert.DoesNotContain(host.OwnerCanary, auditText, StringComparison.Ordinal);
+        Assert.DoesNotContain(principalCanary, auditText, StringComparison.Ordinal);
+        Assert.DoesNotContain(listingId.ToString(), auditText, StringComparison.Ordinal);
+        Assert.DoesNotContain(host.OwnerCanary, logText, StringComparison.Ordinal);
+        Assert.DoesNotContain(principalCanary, logText, StringComparison.Ordinal);
+        Assert.DoesNotContain("exception-secret-canary", logText, StringComparison.Ordinal);
+        Assert.DoesNotContain(host.FullOperatorCredential, logText, StringComparison.Ordinal);
+        meterListener.RecordObservableInstruments();
+        string telemetryText = string.Join('|', telemetryData);
+        Assert.DoesNotContain(host.OwnerCanary, telemetryText, StringComparison.Ordinal);
+        Assert.DoesNotContain(principalCanary, telemetryText, StringComparison.Ordinal);
+        Assert.DoesNotContain("exception-secret-canary", telemetryText, StringComparison.Ordinal);
+        Assert.DoesNotContain(host.FullOperatorCredential, telemetryText, StringComparison.Ordinal);
+        Assert.DoesNotContain(listingId.ToString(), telemetryText, StringComparison.Ordinal);
+        Assert.DoesNotContain("203.0.113.25", telemetryText, StringComparison.Ordinal);
+        Assert.Contains(host.Audit.GetEntriesForTests(), static entry =>
+            entry.Action == "begin-drain" && entry.Result == "succeeded");
+        Assert.Contains(host.Audit.GetEntriesForTests(), static entry =>
+            entry.Action == "revoke-listing" && entry.Result == "rejected");
+        Assert.Contains(host.Audit.GetEntriesForTests(), static entry =>
+            entry.Action == "begin-drain" && entry.Result == "forbidden");
+    }
+
+    private static async Task<HttpResponseMessage> SendAsync(
+        OperatorTestHost host,
+        HttpMethod method,
+        string path,
+        string bearer,
+        object? body = null)
+    {
+        using HttpRequestMessage request = new(method, path);
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", bearer);
+        if (body is not null)
+        {
+            request.Content = JsonContent.Create(body, options: ContractJson.Options);
+        }
+
+        return await host.Client.SendAsync(request);
+    }
+
+    private static void CaptureMeasurement<T>(
+        List<string> destination,
+        Instrument instrument,
+        T value,
+        ReadOnlySpan<KeyValuePair<string, object?>> tags)
+        where T : struct
+    {
+        destination.Add($"{instrument.Name}={value}");
+        destination.AddRange(tags.ToArray().Select(static tag => $"{tag.Key}={tag.Value}"));
+    }
+
+    private sealed class OperatorTestHost : IAsyncDisposable
+    {
+        private readonly WebApplication _application;
+        private int _listingSequence;
+        private bool _udpStarted;
+
+        private OperatorTestHost(
+            WebApplication application,
+            HttpClient client,
+            ManualRendezvousClock clock,
+            InMemoryEphemeralRendezvousStore store,
+            AuditTrail audit,
+            CapturingLogger<AuditTrail> auditLogger,
+            CapturingLoggerProvider allLogs,
+            string publisherCredential,
+            string readOnlyOperatorCredential,
+            string fullOperatorCredential)
+        {
+            _application = application;
+            Client = client;
+            Clock = clock;
+            Store = store;
+            Audit = audit;
+            AuditLogger = auditLogger;
+            AllLogs = allLogs;
+            PublisherCredential = publisherCredential;
+            ReadOnlyOperatorCredential = readOnlyOperatorCredential;
+            FullOperatorCredential = fullOperatorCredential;
+        }
+
+        internal const string OperatorKeyId = "operator-key";
+        internal string OwnerCanary { get; } = "publisher-owner-canary";
+        internal HttpClient Client { get; }
+        internal ManualRendezvousClock Clock { get; }
+        internal InMemoryEphemeralRendezvousStore Store { get; }
+        internal AuditTrail Audit { get; }
+        internal CapturingLogger<AuditTrail> AuditLogger { get; }
+        internal CapturingLoggerProvider AllLogs { get; }
+        internal string PublisherCredential { get; }
+        internal string ReadOnlyOperatorCredential { get; }
+        internal string FullOperatorCredential { get; }
+
+        internal static async Task<OperatorTestHost> StartAsync()
+        {
+            ManualRendezvousClock clock = new(ProvisioningTestData.Now);
+            EphemeralStoreOptions stateOptions = new();
+            InMemoryEphemeralRendezvousStore store = new(stateOptions, clock, clock);
+            SigningKeyOptions publisherKey = ProvisioningTestData.CreateKey();
+            SigningKeyOptions operatorKey = ProvisioningTestData.CreateKey(
+                OperatorKeyId,
+                "operator-secret",
+                credentialKinds: [PrincipalCredentialKind.Operator],
+                gameId: null,
+                environmentId: null);
+            ProvisioningOptions options = ProvisioningTestData.CreateOptions();
+            options.SigningKeys = [publisherKey, operatorKey];
+            ProvisioningRuntime provisioning = ProvisioningRuntime.Create(
+                options,
+                ProvisioningTestData.CreateSecrets("secret-1", "operator-secret"),
+                clock.UtcNow);
+            string publisherCredential = provisioning.Credentials.Issue(
+                ProvisioningTestData.CreateDedicatedPublisher(),
+                clock.UtcNow);
+            string readOnlyCredential = provisioning.Credentials.Issue(
+                new OperatorPrincipal(
+                    "operator-readonly",
+                    clock.UtcNow.AddMinutes(10),
+                    [OperatorPermission.ReadPolicy]),
+                clock.UtcNow);
+            string fullCredential = provisioning.Credentials.Issue(
+                new OperatorPrincipal(
+                    "operator-full",
+                    clock.UtcNow.AddMinutes(10),
+                    Enum.GetValues<OperatorPermission>()),
+                clock.UtcNow);
+            CapturingLogger<AuditTrail> auditLogger = new();
+            CapturingLoggerProvider allLogs = new();
+            EphemeralCapabilityIssuer capabilities = new();
+
+            WebApplicationBuilder builder = WebApplication.CreateBuilder();
+            builder.WebHost.UseUrls("http://127.0.0.1:0");
+            builder.Logging.ClearProviders();
+            builder.Logging.SetMinimumLevel(LogLevel.Debug);
+            builder.Logging.AddProvider(allLogs);
+            builder.Logging.AddFilter(
+                "Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware",
+                LogLevel.None);
+            builder.Services.ConfigureHttpJsonOptions(static json =>
+                ContractJson.Configure(json.SerializerOptions));
+            builder.Services.Configure<RouteHandlerOptions>(static route =>
+                route.ThrowOnBadRequest = true);
+            builder.Services.AddProblemDetails();
+            builder.Services.AddExceptionHandler<RendezvousExceptionHandler>();
+            builder.Services.AddOptions<AbuseProtectionOptions>().Configure(static abuse =>
+            {
+                abuse.OperatorAllowedAddresses = ["127.0.0.1"];
+                abuse.HttpGlobalRequestsPerWindow = 1;
+                abuse.HttpOptionalRequestsPerWindow = 1;
+                abuse.HttpIpPrefixRequestsPerWindow = 1;
+                abuse.HttpOptionalIpPrefixRequestsPerWindow = 1;
+            });
+            builder.Services.AddOptions<AuditOptions>();
+            builder.Services.AddOptions<UdpMediatorOptions>().Configure(static udp =>
+            {
+                udp.ListenAddress = "127.0.0.1";
+                udp.Port = 0;
+            });
+            builder.Services.AddSingleton(provisioning);
+            builder.Services.AddSingleton(provisioning.Policies);
+            builder.Services.AddSingleton(provisioning.Credentials);
+            builder.Services.AddSingleton(provisioning.PublisherAuthorization);
+            builder.Services.AddSingleton(store);
+            builder.Services.AddSingleton<IEphemeralRendezvousStore>(store);
+            builder.Services.AddSingleton<IWallClock>(clock);
+            builder.Services.AddSingleton<IMonotonicClock>(clock);
+            builder.Services.AddSingleton(capabilities);
+            builder.Services.AddSingleton<ISessionCapabilityService>(capabilities);
+            builder.Services.AddSingleton<JoinAttemptCursorCodec>();
+            builder.Services.AddSingleton<JoinAttemptService>();
+            builder.Services.AddSingleton<RendezvousTelemetry>();
+            builder.Services.AddSingleton<AbuseProtectionService>();
+            builder.Services.AddSingleton<NatMediationProcessor>();
+            builder.Services.AddSingleton<UdpMediatorService>();
+            builder.Services.AddSingleton(new ProvisioningReadiness(true));
+            builder.Services.AddSingleton<RendezvousReadiness>();
+            builder.Services.AddSingleton<ILogger<AuditTrail>>(auditLogger);
+            builder.Services.AddSingleton<AuditTrail>();
+            builder.Services.AddSingleton<OperatorService>();
+
+            WebApplication app = builder.Build();
+            app.UseMiddleware<TelemetryMiddleware>();
+            app.UseExceptionHandler();
+            app.UseMiddleware<HttpAbuseProtectionMiddleware>();
+            app.MapOperatorEndpoints();
+            app.MapRendezvousHealthEndpoints();
+            app.MapGet("/test/public", static () => Results.Ok()).WithName("TestPublic");
+            app.MapPost(
+                    "/test/exception",
+                    static IResult () => throw new InvalidOperationException("exception-secret-canary"))
+                .WithName("TestSecretException");
+            await app.StartAsync();
+            IServer server = app.Services.GetRequiredService<IServer>();
+            string address = Assert.Single(server.Features.Get<IServerAddressesFeature>()!.Addresses);
+            return new OperatorTestHost(
+                app,
+                new HttpClient { BaseAddress = new Uri(address) },
+                clock,
+                store,
+                app.Services.GetRequiredService<AuditTrail>(),
+                auditLogger,
+                allLogs,
+                publisherCredential,
+                readOnlyCredential,
+                fullCredential);
+        }
+
+        internal SessionListingId CreateListing(string owner)
+        {
+            StoreResult<StoredListing> result = CreateListingResult(owner, out SessionListingId listingId);
+            Assert.True(result.Succeeded);
+            return listingId;
+        }
+
+        internal StoreResult<StoredListing> CreateListingResult(
+            string owner,
+            out SessionListingId listingId)
+        {
+            int sequence = Interlocked.Increment(ref _listingSequence);
+            listingId = new(Guid.NewGuid());
+            StoreResult<StoredListing> result = Store.CreateListing(new(
+                $"operator-listing-{sequence}",
+                $"operator-request-{sequence}",
+                new ListingDefinition
+                {
+                    ListingId = listingId,
+                    LeaseId = new(Guid.NewGuid()),
+                    Scope = new(new GameId("space-game"), new EnvironmentId("production")),
+                    OwnerSubject = owner,
+                    RegionId = new("eu-central"),
+                    ProtocolVersion = 7,
+                    BuildVersion = "1.0.0",
+                    DisplayName = "Operator test listing",
+                    Visibility = ListingVisibility.Public,
+                    TrustMode = PublisherTrustMode.ManagedDedicated,
+                    CurrentPlayers = 1,
+                    MaximumPlayers = 4,
+                    Metadata = new Dictionary<string, string> { ["mode"] = "online-coop" },
+                    LeaseFingerprint = new("lease-fingerprint"),
+                    HostPresenceHandle = new(Guid.NewGuid()),
+                    HostPresenceFingerprint = new("presence-fingerprint"),
+                    CapabilityDerivationSalt = new string('A', 43),
+                }));
+            return result;
+        }
+
+        internal async Task StartUdpAsync()
+        {
+            await _application.Services.GetRequiredService<UdpMediatorService>()
+                .StartAsync(CancellationToken.None);
+            _udpStarted = true;
+        }
+
+        public async ValueTask DisposeAsync()
+        {
+            Client.Dispose();
+            if (_udpStarted)
+            {
+                await _application.Services.GetRequiredService<UdpMediatorService>()
+                    .StopAsync(CancellationToken.None);
+            }
+            await _application.StopAsync();
+            await _application.DisposeAsync();
+        }
+    }
+}

tests/FinalFactory.Rendezvous.Tests/Provisioning/PrincipalCredentialTests.cs

@@ -94,6 +94,7 @@ public sealed class PrincipalCredentialTests
             CredentialValidationError.SignatureInvalid,
             service.Validate(tampered, ProvisioningTestData.Now).Error);
         Assert.True(keys.Revoke("key-1"));
+        Assert.True(keys.Revoke("key-1"));
         Assert.Equal(
             CredentialValidationError.KeyRevoked,
             service.Validate(token, ProvisioningTestData.Now).Error);

tests/FinalFactory.Rendezvous.Tests/Provisioning/ProductionSecretProviderTests.cs

@@ -0,0 +1,66 @@
+using System.Security.Cryptography;
+using FinalFactory.Rendezvous.Server.Provisioning;
+
+namespace FinalFactory.Rendezvous.Tests.Provisioning;
+
+public sealed class ProductionSecretProviderTests : IDisposable
+{
+    private readonly List<string> _paths = [];
+
+    [Fact]
+    public void ReadsBoundedSecretFromAbsoluteReadOnlyFile()
+    {
+        byte[] expected = RandomNumberGenerator.GetBytes(32);
+        string path = CreateSecretFile(expected);
+        EnvironmentSecretProvider provider = new();
+
+        bool found = provider.TryGetSecret($"file:{path}", out SecretMaterial? material);
+
+        Assert.True(found);
+        using (material)
+        {
+            Assert.Equal(expected, material!.CopyBytes());
+        }
+    }
+
+    [Fact]
+    public void RejectsRelativeSymlinkEmptyAndOversizedFileReferences()
+    {
+        string empty = CreateSecretFile([]);
+        string oversized = CreateSecretFile(new byte[4097]);
+        string target = CreateSecretFile(RandomNumberGenerator.GetBytes(32));
+        string symlink = Path.Combine(Path.GetTempPath(), $"rendezvous-secret-link-{Guid.NewGuid():N}");
+        EnvironmentSecretProvider provider = new();
+
+        Assert.False(provider.TryGetSecret("file:relative-secret", out _));
+        Assert.False(provider.TryGetSecret($"file:{empty}", out _));
+        Assert.False(provider.TryGetSecret($"file:{oversized}", out _));
+        Assert.False(provider.TryGetSecret("file:/tmp/invalid\0path", out _));
+        if (!OperatingSystem.IsWindows())
+        {
+            File.CreateSymbolicLink(symlink, target);
+            _paths.Add(symlink);
+            Assert.False(provider.TryGetSecret($"file:{symlink}", out _));
+        }
+    }
+
+    public void Dispose()
+    {
+        foreach (string path in _paths)
+        {
+            File.Delete(path);
+        }
+    }
+
+    private string CreateSecretFile(byte[] bytes)
+    {
+        string path = Path.Combine(Path.GetTempPath(), $"rendezvous-secret-{Guid.NewGuid():N}");
+        File.WriteAllBytes(path, bytes);
+        if (OperatingSystem.IsLinux() || OperatingSystem.IsMacOS() || OperatingSystem.IsFreeBSD())
+        {
+            File.SetUnixFileMode(path, UnixFileMode.UserRead);
+        }
+        _paths.Add(path);
+        return path;
+    }
+}

tests/FinalFactory.Rendezvous.Tests/Server/Abuse/AbuseProtectionTests.cs

@@ -0,0 +1,533 @@
+using System.Net;
+using System.Text.Json;
+using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Abuse;
+using FinalFactory.Rendezvous.Server.Http;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.HttpOverrides;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+
+namespace FinalFactory.Rendezvous.Tests.Server.Abuse;
+
+public sealed class AbuseProtectionTests
+{
+    [Fact]
+    public void Ipv4AndIpv6PrefixesShareBudgetsAndRecoverAfterTheWindow()
+    {
+        ManualTimeProvider time = new(new DateTimeOffset(2026, 7, 16, 12, 0, 0, TimeSpan.Zero));
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.HttpIpPrefixRequestsPerWindow = 2;
+        AbuseProtectionService protection = new(Options.Create(options), time);
+
+        AssertAccepted(protection, IPAddress.Parse("198.51.100.10"), "BrowseSessions");
+        AssertAccepted(protection, IPAddress.Parse("198.51.100.200"), "BrowseSessions");
+        AssertRejected(protection, IPAddress.Parse("198.51.100.99"), "BrowseSessions");
+
+        time.Advance(TimeSpan.FromSeconds(1));
+        AssertAccepted(protection, IPAddress.Parse("198.51.100.99"), "BrowseSessions");
+
+        options = PermissiveOptions();
+        options.HttpIpPrefixRequestsPerWindow = 1;
+        protection = new(Options.Create(options), time);
+        AssertAccepted(protection, IPAddress.Parse("2606:4700:1234:5600::1"), "GetSession");
+        AssertRejected(protection, IPAddress.Parse("2606:4700:1234:56ff::2"), "GetSession");
+        AssertAccepted(protection, IPAddress.Parse("2606:4700:1234:5700::2"), "GetSession");
+    }
+
+    [Fact]
+    public void PrincipalConcurrencyIsReleasedAndRejectedCallsDoNotConsumeRate()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.HttpPrincipalConcurrency = 1;
+        options.HttpPrincipalRequestsPerWindow = 2;
+        AbuseProtectionService protection = new(Options.Create(options));
+
+        Assert.True(protection.TryAcquireHttpIdentity(
+            "RegisterSession", "game/prod", "publisher-1", null, out var first, out _));
+        Assert.False(protection.TryAcquireHttpIdentity(
+            "RegisterSession", "game/prod", "publisher-1", null, out _, out _));
+        first!.Dispose();
+
+        Assert.True(protection.TryAcquireHttpIdentity(
+            "RegisterSession", "game/prod", "publisher-1", null, out var second, out _));
+        second!.Dispose();
+        Assert.False(protection.TryAcquireHttpIdentity(
+            "RegisterSession", "game/prod", "publisher-1", null, out _, out _));
+    }
+
+    [Fact]
+    public void TrackerCapacityFailsClosedWithoutGrowingAndAWindowResetRecovers()
+    {
+        ManualTimeProvider time = new(new DateTimeOffset(2026, 7, 16, 12, 0, 0, TimeSpan.Zero));
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.MaxTrackedKeys = 10;
+        options.UdpTrackedKeyLimit = 0;
+        AbuseProtectionService protection = new(Options.Create(options), time);
+
+        AssertAccepted(protection, IPAddress.Parse("198.51.100.1"), "GetSession");
+        AssertRejected(protection, IPAddress.Parse("203.0.113.1"), "GetSession");
+        Assert.InRange(protection.TrackedKeyCount, 1, options.MaxTrackedKeys);
+
+        time.Advance(TimeSpan.FromSeconds(1));
+        AssertAccepted(protection, IPAddress.Parse("203.0.113.1"), "GetSession");
+        Assert.InRange(protection.TrackedKeyCount, 1, options.MaxTrackedKeys);
+    }
+
+    [Fact]
+    public void OptionalTrafficCannotConsumeTheLeaseOperationReserve()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.HttpGlobalRequestsPerWindow = 3;
+        options.HttpOptionalRequestsPerWindow = 2;
+        options.HttpIpPrefixRequestsPerWindow = 3;
+        options.HttpOptionalIpPrefixRequestsPerWindow = 2;
+        AbuseProtectionService protection = new(Options.Create(options));
+        IPAddress source = IPAddress.Parse("198.51.100.10");
+
+        Assert.True(protection.IsOperatorSourceAllowed(source));
+        Assert.True(protection.IsOperatorSourceAllowed(IPAddress.Parse("::ffff:198.51.100.10")));
+        Assert.False(protection.IsOperatorSourceAllowed(IPAddress.Parse("198.51.100.11")));
+        AssertAccepted(protection, source, "BrowseSessions");
+        AssertAccepted(protection, source, "BrowseSessions");
+        AssertRejected(protection, source, "BrowseSessions");
+        AssertAccepted(protection, source, "RenewSessionLease");
+        AssertRejected(protection, source, "RenewSessionLease");
+    }
+
+    [Fact]
+    public void PublicSaturationCannotConsumeTheOperatorPartition()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.HttpGlobalRequestsPerWindow = 1;
+        options.HttpOptionalRequestsPerWindow = 1;
+        options.OperatorGlobalRequestsPerWindow = 1;
+        AbuseProtectionService protection = new(Options.Create(options));
+        IPAddress source = IPAddress.Parse("198.51.100.10");
+
+        AssertAccepted(protection, source, "BrowseSessions");
+        AssertRejected(protection, source, "BrowseSessions");
+        Assert.True(protection.TryAcquireOperatorIngress(source, out var lease, out _));
+        lease!.Dispose();
+        Assert.False(protection.TryAcquireOperatorIngress(source, out _, out _));
+    }
+
+    [Fact]
+    public async Task DeniedOperatorSourcesConsumeTheBoundedPublicPartition()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.OperatorAllowedAddresses = ["192.0.2.10"];
+        options.HttpGlobalRequestsPerWindow = 1;
+        options.HttpOptionalRequestsPerWindow = 1;
+        options.HttpIpPrefixRequestsPerWindow = 1;
+        options.HttpOptionalIpPrefixRequestsPerWindow = 1;
+        AbuseProtectionService protection = new(Options.Create(options));
+        bool dispatched = false;
+        HttpAbuseProtectionMiddleware middleware = new(
+            _ =>
+            {
+                dispatched = true;
+                return Task.CompletedTask;
+            },
+            protection);
+
+        DefaultHttpContext first = Context("198.51.100.10");
+        first.SetEndpoint(new Endpoint(
+            _ => Task.CompletedTask,
+            new EndpointMetadataCollection(new EndpointNameMetadata("GetOperatorStatus")),
+            "operator-status"));
+        await middleware.InvokeAsync(first);
+        Assert.Equal(StatusCodes.Status404NotFound, first.Response.StatusCode);
+
+        DefaultHttpContext repeated = Context("198.51.100.10");
+        repeated.SetEndpoint(first.GetEndpoint());
+        await middleware.InvokeAsync(repeated);
+        Assert.Equal(StatusCodes.Status429TooManyRequests, repeated.Response.StatusCode);
+        Assert.False(dispatched);
+    }
+
+    [Fact]
+    public void ResourceBudgetsRemainIsolatedAcrossTenantAndPrincipalScopes()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.HttpResourceRequestsPerWindow = 1;
+        AbuseProtectionService protection = new(Options.Create(options));
+
+        Assert.True(protection.TryAcquireHttpIdentity(
+            "UpdateSession", IPAddress.Parse("198.51.100.10"),
+            "game-a/prod", "publisher", "listing", out var first, out _));
+        first!.Dispose();
+        Assert.False(protection.TryAcquireHttpIdentity(
+            "UpdateSession", IPAddress.Parse("198.51.100.10"),
+            "game-a/prod", "publisher", "listing", out _, out _));
+        Assert.True(protection.TryAcquireHttpIdentity(
+            "UpdateSession", IPAddress.Parse("203.0.113.10"),
+            "game-b/prod", "publisher", "listing", out var second, out _));
+        second!.Dispose();
+        Assert.True(protection.TryAcquireHttpIdentity(
+            "UpdateSession", IPAddress.Parse("192.0.2.10"),
+            "game-a/prod", "other-publisher", "listing", out var third, out _));
+        third!.Dispose();
+    }
+
+    [Fact]
+    public void RotatingCredentialsCannotBypassIndependentResourceBudgets()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.HttpResourceRequestsPerWindow = 2;
+        options.UdpResourceDatagramsPerWindow = 2;
+        AbuseProtectionService protection = new(Options.Create(options));
+
+        for (int index = 1; index <= 2; index++)
+        {
+            Assert.True(protection.TryAcquireHttpIdentity(
+                "CancelJoinAttempt", null, $"capability-{index}", "attempt", out var lease, out _));
+            lease!.Dispose();
+            Assert.True(protection.TryAcceptUdpIdentity(
+                "Client", $"capability-{index}", "mediation-handle"));
+        }
+
+        Assert.False(protection.TryAcquireHttpIdentity(
+            "CancelJoinAttempt", null, "capability-3", "attempt", out _, out _));
+        Assert.False(protection.TryAcceptUdpIdentity(
+            "Client", "capability-3", "mediation-handle"));
+    }
+
+    [Fact]
+    public void UdpWireOperationsHaveIndependentBoundedIngressBudgets()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.UdpOperationDatagramsPerWindow = 1;
+        AbuseProtectionService protection = new(Options.Create(options));
+        IPAddress source = IPAddress.Parse("198.51.100.10");
+
+        Assert.True(protection.TryAcceptUdpIngress(source, "frozen"));
+        Assert.False(protection.TryAcceptUdpIngress(source, "frozen"));
+        Assert.True(protection.TryAcceptUdpIngress(source, "litenet-or-invalid"));
+        Assert.False(protection.TryAcceptUdpIngress(source, "litenet-or-invalid"));
+    }
+
+    [Fact]
+    public void UdpTrackerExhaustionCannotConsumeTheCriticalHttpKeyReserve()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.MaxTrackedKeys = 28;
+        options.CriticalTrackedKeyReserve = 16;
+        options.UdpTrackedKeyLimit = 12;
+        AbuseProtectionService protection = new(Options.Create(options));
+
+        for (int index = 1; index <= 3; index++)
+        {
+            IPAddress address = IPAddress.Parse($"198.51.{index}.1");
+            _ = protection.TryAcceptUdpIngress(address, "raw");
+            _ = protection.TryAcceptUdpIdentity("Client", $"capability-{index}", $"resource-{index}");
+        }
+
+        Assert.InRange(protection.TrackedKeyCount, 1, 12);
+        Assert.True(protection.TryAcquireHttpIngress(
+            IPAddress.Parse("203.0.113.10"),
+            "RenewSessionLease",
+            out var ingress,
+            out _));
+        Assert.True(protection.TryAcquireHttpIdentity(
+            "RenewSessionLease",
+            "game/prod",
+            "publisher",
+            "listing",
+            out var identity,
+            out _));
+        identity!.Dispose();
+        ingress!.Dispose();
+        Assert.InRange(protection.TrackedKeyCount, 1, options.MaxTrackedKeys);
+    }
+
+    [Fact]
+    public async Task HttpOverloadIsTypedAndOversizedBodiesAreRejectedBeforeDispatch()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.HttpIpPrefixRequestsPerWindow = 1;
+        AbuseProtectionService protection = new(Options.Create(options));
+        int dispatched = 0;
+        HttpAbuseProtectionMiddleware middleware = new(
+            _ =>
+            {
+                dispatched++;
+                return Task.CompletedTask;
+            },
+            protection);
+
+        DefaultHttpContext accepted = Context("198.51.100.10");
+        await middleware.InvokeAsync(accepted);
+        Assert.Equal(1, dispatched);
+
+        DefaultHttpContext limited = Context("198.51.100.11");
+        await middleware.InvokeAsync(limited);
+        Assert.Equal(StatusCodes.Status429TooManyRequests, limited.Response.StatusCode);
+        Assert.Equal("1", limited.Response.Headers.RetryAfter);
+        limited.Response.Body.Position = 0;
+        ApiError? error = await JsonSerializer.DeserializeAsync<ApiError>(
+            limited.Response.Body,
+            ContractJson.Options);
+        Assert.Equal(RendezvousErrorCode.RateLimited, error?.Code);
+        Assert.Equal(1, error?.RetryAfterSeconds);
+        Assert.Equal(1, dispatched);
+
+        DefaultHttpContext oversized = Context("203.0.113.1");
+        oversized.Request.ContentLength = ContractLimits.HttpRequestMaxBytes + 1;
+        await middleware.InvokeAsync(oversized);
+        Assert.Equal(StatusCodes.Status413PayloadTooLarge, oversized.Response.StatusCode);
+        Assert.Equal(1, dispatched);
+
+        DefaultHttpContext repeatedOversized = Context("203.0.113.2");
+        repeatedOversized.Request.ContentLength = ContractLimits.HttpRequestMaxBytes + 1;
+        await middleware.InvokeAsync(repeatedOversized);
+        Assert.Equal(StatusCodes.Status429TooManyRequests, repeatedOversized.Response.StatusCode);
+        Assert.Equal(1, dispatched);
+    }
+
+    [Fact]
+    public void DeterministicHostileUdpCorpusNeverThrowsOrAcceptsOversizedDatagrams()
+    {
+        const int seed = 0x15_2026;
+        Random random = new(seed);
+        for (int iteration = 0; iteration < 10_000; iteration++)
+        {
+            int length = random.Next(0, ContractLimits.UdpDatagramMaxBytes + 257);
+            byte[] payload = new byte[length];
+            random.NextBytes(payload);
+
+            bool decoded = RendezvousUdpCodec.TryDecode(
+                payload,
+                out PresenceDatagram? datagram,
+                out UdpDecodeError error);
+            if (length > ContractLimits.UdpDatagramMaxBytes)
+            {
+                Assert.False(decoded);
+                Assert.Null(datagram);
+                Assert.Equal(UdpDecodeError.DatagramTooLarge, error);
+            }
+        }
+    }
+
+    [Fact]
+    public void ConcurrentAbusiveBurstStaysBoundedAndCannotBlockCriticalHttp()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.MaxTrackedKeys = 2_000;
+        options.UdpTrackedKeyLimit = 1_000;
+        options.CriticalTrackedKeyReserve = 100;
+        options.UdpGlobalDatagramsPerWindow = 100_000;
+        options.UdpIpPrefixDatagramsPerWindow = 100_000;
+        options.UdpOperationDatagramsPerWindow = 100_000;
+        AbuseProtectionService protection = new(Options.Create(options));
+        IPAddress source = IPAddress.Parse("198.51.100.10");
+
+        Parallel.For(0, 20_000, index =>
+        {
+            _ = protection.TryAcceptUdpIngress(source, "raw");
+            _ = protection.TryAcceptUdpIdentity(
+                "Client",
+                $"capability-{index}",
+                $"resource-{index}");
+        });
+
+        Assert.InRange(protection.TrackedKeyCount, 1, options.UdpTrackedKeyLimit);
+        Assert.True(protection.TryAcquireHttpIngress(
+            IPAddress.Parse("203.0.113.10"),
+            "RenewSessionLease",
+            out var lease,
+            out _));
+        lease!.Dispose();
+        Assert.InRange(protection.TrackedKeyCount, 1, options.MaxTrackedKeys);
+    }
+
+    [Fact]
+    public void SteadyStateUdpAdmissionHasABoundedAllocationBudget()
+    {
+        AbuseProtectionOptions options = PermissiveOptions();
+        options.UdpGlobalDatagramsPerWindow = 100_000;
+        options.UdpIpPrefixDatagramsPerWindow = 100_000;
+        options.UdpOperationDatagramsPerWindow = 100_000;
+        options.UdpCapabilityDatagramsPerWindow = 100_000;
+        options.UdpResourceDatagramsPerWindow = 100_000;
+        AbuseProtectionService protection = new(Options.Create(options));
+        IPAddress source = IPAddress.Parse("198.51.100.10");
+        _ = protection.TryAcceptUdpIngress(source, "frozen");
+        _ = protection.TryAcceptUdpIdentity("Host", source, "capability", "resource");
+
+        long before = GC.GetAllocatedBytesForCurrentThread();
+        for (int iteration = 0; iteration < 10_000; iteration++)
+        {
+            Assert.True(protection.TryAcceptUdpIngress(source, "frozen"));
+            Assert.True(protection.TryAcceptUdpIdentity(
+                "Host", source, "capability", "resource"));
+        }
+
+        long allocated = GC.GetAllocatedBytesForCurrentThread() - before;
+        Assert.InRange(allocated, 0, 40_000_000);
+    }
+
+    [Fact]
+    public void DeterministicHttpAndCredentialParserCorpusHasOnlyTypedRejections()
+    {
+        const int seed = 0x15_4A50;
+        Random random = new(seed);
+        for (int iteration = 0; iteration < 5_000; iteration++)
+        {
+            byte[] bytes = new byte[random.Next(0, 1_025)];
+            random.NextBytes(bytes);
+            try
+            {
+                _ = JsonSerializer.Deserialize<RegisterSessionRequest>(bytes, ContractJson.Options);
+            }
+            catch (JsonException)
+            {
+            }
+
+            string token = Convert.ToBase64String(bytes);
+            Assert.False(NatPunchRequestTokenCodec.TryDecode(token, out _));
+            Assert.False(NatIntroductionTokenCodec.TryDecode(token, out _));
+        }
+    }
+
+    [Fact]
+    public void SecretFingerprintsAreStableBoundedAndDoNotContainHostileInput()
+    {
+        const string hostile = "<script>steal('token')</script>\r\nAuthorization: secret";
+        string fingerprint = AbuseProtectionService.FingerprintSecret(hostile);
+
+        Assert.Equal(fingerprint, AbuseProtectionService.FingerprintSecret(hostile));
+        Assert.Equal(24, fingerprint.Length);
+        Assert.DoesNotContain("script", fingerprint, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("secret", fingerprint, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task ExceptionResponsesPreservePayloadStatusWithoutEchoingHostileDetails()
+    {
+        const string canary = "credential-canary <script> endpoint=203.0.113.8:9000";
+        DefaultHttpContext context = Context("198.51.100.10");
+        RendezvousExceptionHandler handler = new(
+            NullLogger<RendezvousExceptionHandler>.Instance);
+
+        Assert.True(await handler.TryHandleAsync(
+            context,
+            new BadHttpRequestException(canary, StatusCodes.Status413PayloadTooLarge),
+            CancellationToken.None));
+
+        Assert.Equal(StatusCodes.Status413PayloadTooLarge, context.Response.StatusCode);
+        context.Response.Body.Position = 0;
+        using StreamReader reader = new(context.Response.Body);
+        string body = await reader.ReadToEndAsync();
+        Assert.DoesNotContain(canary, body, StringComparison.Ordinal);
+        Assert.DoesNotContain("203.0.113.8", body, StringComparison.Ordinal);
+        Assert.DoesNotContain("script", body, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task ForwardedSourcesAreDefaultDenyExactProxyOnlyAndSingleHop()
+    {
+        AbuseProtectionOptions disabled = new();
+        Assert.False(TrustedProxyForwarding.IsEnabled(disabled));
+
+        AbuseProtectionOptions enabled = new()
+        {
+            TrustedProxyAddresses = ["192.0.2.10"],
+        };
+        Assert.True(TrustedProxyForwarding.IsEnabled(enabled));
+        ForwardedHeadersOptions forwarded = new();
+        TrustedProxyForwarding.Configure(forwarded, enabled);
+        ForwardedHeadersMiddleware middleware = new(
+            _ => Task.CompletedTask,
+            NullLoggerFactory.Instance,
+            Options.Create(forwarded));
+
+        DefaultHttpContext trusted = Context("192.0.2.10");
+        trusted.Request.Headers["X-Forwarded-For"] = "198.51.100.7";
+        await middleware.Invoke(trusted);
+        Assert.Equal(IPAddress.Parse("198.51.100.7"), trusted.Connection.RemoteIpAddress);
+
+        DefaultHttpContext untrusted = Context("192.0.2.11");
+        untrusted.Request.Headers["X-Forwarded-For"] = "198.51.100.8";
+        await middleware.Invoke(untrusted);
+        Assert.Equal(IPAddress.Parse("192.0.2.11"), untrusted.Connection.RemoteIpAddress);
+
+        DefaultHttpContext multiHop = Context("192.0.2.10");
+        multiHop.Request.Headers["X-Forwarded-For"] = "198.51.100.9, 203.0.113.9";
+        await middleware.Invoke(multiHop);
+        Assert.Equal(IPAddress.Parse("203.0.113.9"), multiHop.Connection.RemoteIpAddress);
+    }
+
+    private static DefaultHttpContext Context(string address)
+    {
+        DefaultHttpContext context = new();
+        context.Connection.RemoteIpAddress = IPAddress.Parse(address);
+        context.Response.Body = new MemoryStream();
+        return context;
+    }
+
+    private static void AssertAccepted(
+        AbuseProtectionService protection,
+        IPAddress address,
+        string operation)
+    {
+        Assert.True(protection.TryAcquireHttpIngress(
+            address, operation, out var lease, out _));
+        lease!.Dispose();
+    }
+
+    private static void AssertRejected(
+        AbuseProtectionService protection,
+        IPAddress address,
+        string operation) => Assert.False(protection.TryAcquireHttpIngress(
+        address, operation, out _, out _));
+
+    private static AbuseProtectionOptions PermissiveOptions() => new()
+    {
+        WindowSeconds = 1,
+        MaxTrackedKeys = 10_000,
+        CriticalTrackedKeyReserve = 0,
+        UdpTrackedKeyLimit = 5_000,
+        HealthGlobalRequestsPerWindow = 10_000,
+        HealthGlobalConcurrency = 10_000,
+        HealthIpPrefixRequestsPerWindow = 10_000,
+        HealthIpPrefixConcurrency = 1_000,
+        OperatorAllowedAddresses = ["198.51.100.10"],
+        OperatorGlobalRequestsPerWindow = 10_000,
+        OperatorGlobalConcurrency = 10_000,
+        OperatorIpPrefixRequestsPerWindow = 10_000,
+        OperatorIpPrefixConcurrency = 1_000,
+        HttpGlobalRequestsPerWindow = 10_000,
+        HttpOptionalRequestsPerWindow = 9_000,
+        HttpIpPrefixRequestsPerWindow = 10_000,
+        HttpOptionalIpPrefixRequestsPerWindow = 9_000,
+        HttpOperationRequestsPerWindow = 10_000,
+        HttpTenantRequestsPerWindow = 10_000,
+        HttpPrincipalRequestsPerWindow = 10_000,
+        HttpResourceRequestsPerWindow = 10_000,
+        HttpGlobalConcurrency = 10_000,
+        HttpOptionalConcurrency = 9_000,
+        HttpIpPrefixConcurrency = 10_000,
+        HttpOptionalIpPrefixConcurrency = 9_000,
+        HttpOperationConcurrency = 10_000,
+        HttpTenantConcurrency = 10_000,
+        HttpPrincipalConcurrency = 10_000,
+        HttpResourceConcurrency = 10_000,
+        UdpGlobalDatagramsPerWindow = 10_000,
+        UdpIpPrefixDatagramsPerWindow = 10_000,
+        UdpOperationDatagramsPerWindow = 10_000,
+        UdpCapabilityDatagramsPerWindow = 10_000,
+        UdpResourceDatagramsPerWindow = 10_000,
+    };
+
+    private sealed class ManualTimeProvider(DateTimeOffset utcNow) : TimeProvider
+    {
+        private DateTimeOffset _utcNow = utcNow;
+
+        public override DateTimeOffset GetUtcNow() => _utcNow;
+
+        public void Advance(TimeSpan duration) => _utcNow += duration;
+    }
+}

tests/FinalFactory.Rendezvous.Tests/Server/NatMediationProcessorTests.cs

@@ -1,15 +1,56 @@
 using System.Collections.Concurrent;
 using System.Net;
 using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Abuse;
 using FinalFactory.Rendezvous.Server.JoinAttempts;
 using FinalFactory.Rendezvous.Server.State;
 using FinalFactory.Rendezvous.Server.Transport;
 using FinalFactory.Rendezvous.Tests.JoinAttempts;
+using Microsoft.Extensions.Options;
 
 namespace FinalFactory.Rendezvous.Tests.Server;
 
 public sealed class NatMediationProcessorTests
 {
+    [Fact]
+    public void LimitedAuthenticatedUdpTrafficIsSilentlyDroppedWithoutAnIntroduction()
+    {
+        using JoinAttemptFixture fixture = new();
+        (RegisterSessionResponse registration, _) = fixture.CreateHost(bindPresence: false);
+        AbuseProtectionOptions options = new()
+        {
+            UdpCapabilityDatagramsPerWindow = 1,
+            UdpResourceDatagramsPerWindow = 10,
+        };
+        AbuseProtectionService protection = new(Options.Create(options));
+        NatMediationProcessor processor = new(
+            fixture.Sessions.Store,
+            fixture.Sessions.Capabilities,
+            fixture.Service,
+            protection);
+        CaptureIntroductionSink sink = new();
+        string token = NatPunchRequestTokenCodec.Encode(
+            NatPunchPeerRole.HostPresence,
+            registration.HostPresenceHandle,
+            registration.HostPresenceCapability);
+
+        Assert.Equal(
+            NatMediationResult.HostPresenceAccepted,
+            processor.ProcessRequest(
+                Endpoint("192.168.1.50", 40_000),
+                Endpoint("203.0.113.77", 51_234),
+                token,
+                sink));
+        Assert.Equal(
+            NatMediationResult.Dropped,
+            processor.ProcessRequest(
+                Endpoint("192.168.1.50", 40_000),
+                Endpoint("203.0.113.77", 51_234),
+                token,
+                sink));
+        Assert.Empty(sink.Plans);
+    }
+
     [Fact]
     public void AuthenticatedHostPresenceUsesTheObservedGameplaySocket()
     {

tests/FinalFactory.Rendezvous.Tests/Server/UdpMediatorServiceTests.cs

@@ -1,6 +1,7 @@
 using System.Net;
 using System.Net.Sockets;
 using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Abuse;
 using FinalFactory.Rendezvous.Server.Transport;
 using FinalFactory.Rendezvous.Tests.JoinAttempts;
 using LiteNetLib;
@@ -86,8 +87,10 @@ public sealed class UdpMediatorServiceTests
         await service.StopAsync(timeout.Token);
     }
 
-    [Fact]
-    public async Task NativeLiteNetLibRequestsIntroduceTheAuthorizedPair()
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public async Task NativeLiteNetLibRequestsIntroduceTheAuthorizedPair(bool restartMediator)
     {
         using CancellationTokenSource timeout = new(TimeSpan.FromSeconds(5));
         using JoinAttemptFixture fixture = new();
@@ -103,18 +106,6 @@ public sealed class UdpMediatorServiceTests
             fixture.Sessions.Store,
             fixture.Sessions.Capabilities,
             fixture.Service);
-        using UdpMediatorService service = new(
-            Options.Create(new UdpMediatorOptions
-            {
-                ListenAddress = IPAddress.Loopback.ToString(),
-                Port = 0,
-                MaxDatagramsPerPoll = 8,
-                PollIntervalMilliseconds = 1,
-            }),
-            NullLogger<UdpMediatorService>.Instance,
-            processor);
-        await service.StartAsync(timeout.Token);
-
         EventBasedNetListener hostListener = new();
         EventBasedNetListener clientListener = new();
         NetManager host = new(hostListener) { NatPunchEnabled = true };
@@ -127,11 +118,90 @@ public sealed class UdpMediatorServiceTests
         clientPunch.NatIntroductionSuccess += (_, _, ticket) => clientTickets.Add(ticket);
         host.NatPunchModule.Init(hostPunch);
         client.NatPunchModule.Init(clientPunch);
+        UdpMediatorService? service = null;
+        bool serviceStarted = false;
 
         try
         {
+            service = CreateMediator(processor, port: 0);
+            await service.StartAsync(timeout.Token);
+            serviceStarted = true;
             Assert.True(host.Start(0));
             Assert.True(client.Start(0));
+            if (restartMediator)
+            {
+                await AssertNativeIntroductionAsync(
+                    service,
+                    host,
+                    client,
+                    hostTickets,
+                    clientTickets,
+                    created,
+                    hostAttempt,
+                    expectedCount: 1,
+                    cancellationToken: timeout.Token);
+                created = fixture.Create(registration.ListingId, "native-litenet-after-restart");
+                hostAttempt = fixture.Service.BrowseForHost(
+                    registration.ListingId,
+                    ContractLimits.ContractVersion,
+                    registration.LeaseToken,
+                    ContractLimits.BrowserPageMaxItems,
+                    null).Value!.Items.Single(item => item.AttemptId == created.AttemptId);
+                int boundPort = Assert.IsType<IPEndPoint>(service.LocalEndpoint).Port;
+                await service.StopAsync(timeout.Token);
+                serviceStarted = false;
+                service.Dispose();
+                service = null;
+                service = CreateMediator(processor, boundPort);
+                await service.StartAsync(timeout.Token);
+                serviceStarted = true;
+                Assert.Equal(boundPort, Assert.IsType<IPEndPoint>(service.LocalEndpoint).Port);
+            }
+
+            await AssertNativeIntroductionAsync(
+                service,
+                host,
+                client,
+                hostTickets,
+                clientTickets,
+                created,
+                hostAttempt,
+                expectedCount: restartMediator ? 2 : 1,
+                cancellationToken: timeout.Token);
+        }
+        finally
+        {
+            host.Stop();
+            client.Stop();
+            if (service is not null)
+            {
+                try
+                {
+                    if (serviceStarted)
+                    {
+                        using CancellationTokenSource cleanup = new(TimeSpan.FromSeconds(5));
+                        await service.StopAsync(cleanup.Token);
+                    }
+                }
+                finally
+                {
+                    service.Dispose();
+                }
+            }
+        }
+    }
+
+    private static async Task AssertNativeIntroductionAsync(
+        UdpMediatorService service,
+        NetManager host,
+        NetManager client,
+        List<string> hostTickets,
+        List<string> clientTickets,
+        CreateJoinAttemptResponse created,
+        HostJoinAttempt hostAttempt,
+        int expectedCount,
+        CancellationToken cancellationToken)
+    {
         IPEndPoint mediator = Assert.IsType<IPEndPoint>(service.LocalEndpoint);
         host.NatPunchModule.SendNatIntroduceRequest(
             mediator,
@@ -146,18 +216,23 @@ public sealed class UdpMediatorServiceTests
                 created.MediationHandle,
                 created.ClientPunchCapability));
 
-            while ((hostTickets.Count == 0 || clientTickets.Count == 0)
-                   && !timeout.IsCancellationRequested)
+        while ((hostTickets.Distinct(StringComparer.Ordinal).Count() < expectedCount
+                || clientTickets.Distinct(StringComparer.Ordinal).Count() < expectedCount)
+               && !cancellationToken.IsCancellationRequested)
         {
             host.PollEvents();
             host.NatPunchModule.PollEvents();
             client.PollEvents();
             client.NatPunchModule.PollEvents();
-                await Task.Delay(5, timeout.Token);
+            await Task.Delay(5, cancellationToken);
         }
 
-            string hostTicket = Assert.Single(hostTickets.Distinct(StringComparer.Ordinal));
-            string clientTicket = Assert.Single(clientTickets.Distinct(StringComparer.Ordinal));
+        List<string> distinctHostTickets = hostTickets.Distinct(StringComparer.Ordinal).ToList();
+        List<string> distinctClientTickets = clientTickets.Distinct(StringComparer.Ordinal).ToList();
+        Assert.Equal(expectedCount, distinctHostTickets.Count);
+        Assert.Equal(expectedCount, distinctClientTickets.Count);
+        string hostTicket = distinctHostTickets[^1];
+        string clientTicket = distinctClientTickets[^1];
         Assert.Equal(hostTicket, clientTicket);
         Assert.True(NatIntroductionTokenCodec.TryDecode(
             hostTicket,
@@ -166,13 +241,17 @@ public sealed class UdpMediatorServiceTests
         Assert.Equal(created.AttemptId, introduction.AttemptId);
         Assert.Equal(43, introduction.ConnectionTicket.Length);
     }
-        finally
+
+    private static UdpMediatorService CreateMediator(NatMediationProcessor processor, int port) => new(
+        Options.Create(new UdpMediatorOptions
         {
-            host.Stop();
-            client.Stop();
-            await service.StopAsync(CancellationToken.None);
-        }
-    }
+            ListenAddress = IPAddress.Loopback.ToString(),
+            Port = port,
+            MaxDatagramsPerPoll = 8,
+            PollIntervalMilliseconds = 1,
+        }),
+        NullLogger<UdpMediatorService>.Instance,
+        processor);
 
     [Fact]
     public async Task FrozenV1EnvelopeIsConsumedOnTheLiteNetSocketWithinAmplificationBudget()
@@ -249,10 +328,12 @@ public sealed class UdpMediatorServiceTests
     {
         using CancellationTokenSource timeout = new(TimeSpan.FromSeconds(5));
         using JoinAttemptFixture fixture = new();
+        AbuseProtectionService protection = new(Options.Create(new AbuseProtectionOptions()));
         NatMediationProcessor processor = new(
             fixture.Sessions.Store,
             fixture.Sessions.Capabilities,
-            fixture.Service);
+            fixture.Service,
+            protection);
         using UdpMediatorService service = new(
             Options.Create(new UdpMediatorOptions
             {
@@ -280,6 +361,7 @@ public sealed class UdpMediatorServiceTests
             using CancellationTokenSource noResponse = new(TimeSpan.FromMilliseconds(150));
             await Assert.ThrowsAnyAsync<OperationCanceledException>(async () =>
                 await sender.ReceiveAsync(noResponse.Token));
+            Assert.InRange(protection.TrackedKeyCount, 3, 5);
         }
         finally
         {

tests/FinalFactory.Rendezvous.Tests/Sessions/SessionHttpEndpointTests.cs

@@ -4,6 +4,7 @@ using System.Net.Http.Json;
 using System.Text;
 using System.Text.Json;
 using FinalFactory.Rendezvous.Contracts;
+using FinalFactory.Rendezvous.Server.Abuse;
 using FinalFactory.Rendezvous.Server.Browser;
 using FinalFactory.Rendezvous.Server.Http;
 using FinalFactory.Rendezvous.Server.Provisioning;
@@ -44,6 +45,8 @@ public sealed class SessionHttpEndpointTests
             options.ThrowOnBadRequest = true);
         builder.Services.AddProblemDetails();
         builder.Services.AddExceptionHandler<RendezvousExceptionHandler>();
+        builder.Services.AddOptions<AbuseProtectionOptions>();
+        builder.Services.AddSingleton<AbuseProtectionService>();
         builder.Services.AddSingleton(provisioning);
         builder.Services.AddSingleton(provisioning.Credentials);
         builder.Services.AddSingleton(provisioning.PublisherAuthorization);
@@ -57,6 +60,7 @@ public sealed class SessionHttpEndpointTests
         builder.Services.AddSingleton<SessionBrowserService>();
         await using WebApplication app = builder.Build();
         app.UseExceptionHandler();
+        app.UseMiddleware<HttpAbuseProtectionMiddleware>();
         app.MapRendezvousContractEndpoints();
         await app.StartAsync();
         IServer server = app.Services.GetRequiredService<IServer>();

tests/FinalFactory.Rendezvous.Tests/State/InMemoryEphemeralRendezvousStoreTests.cs

@@ -5,6 +5,57 @@ namespace FinalFactory.Rendezvous.Tests.State;
 
 public sealed class InMemoryEphemeralRendezvousStoreTests
 {
+    [Fact]
+    public void DeterministicHostileStateTransitionsStayTypedAndCapacityBounded()
+    {
+        const int seed = 0x15_57A7E;
+        Random random = new(seed);
+        EphemeralStateFixture fixture = new(new EphemeralStoreOptions
+        {
+            MaxJoinAttempts = 32,
+        });
+        StoredListing listing = fixture.CreateVisibleListing(out _);
+
+        for (int iteration = 0; iteration < 1_000; iteration++)
+        {
+            CreateJoinAttemptCommand command = fixture.AttemptCommand(listing);
+            command = random.Next(4) switch
+            {
+                0 => command with
+                {
+                    Scope = new(new GameId("other-game"), new EnvironmentId("test")),
+                },
+                1 => command with { ProtocolVersion = command.ProtocolVersion + 1 },
+                _ => command,
+            };
+            StoreResult<StoredJoinAttempt> created = fixture.Store.CreateJoinAttempt(command);
+            Assert.True(Enum.IsDefined(created.Code));
+            if (!created.Succeeded || created.Value is null)
+            {
+                continue;
+            }
+
+            SecretFingerprint supplied = random.Next(3) == 0
+                ? EphemeralStateFixture.Fingerprint($"wrong-{iteration}")
+                : created.Value.ClientCapabilityFingerprint;
+            StoreResult<StoredJoinAttempt> bound = fixture.Store.BindAttemptEndpoint(new(
+                created.Value.MediationHandle,
+                AttemptPeerRole.Client,
+                supplied,
+                EphemeralStateFixture.OtherPublicEndpoint(20_000 + iteration),
+                null));
+            Assert.True(Enum.IsDefined(bound.Code));
+        }
+
+        StoreResult<IReadOnlyList<StoredJoinAttempt>> attempts =
+            fixture.Store.BrowseHostJoinAttempts(new(
+                listing.Definition.ListingId,
+                listing.Definition.LeaseFingerprint,
+                100));
+        Assert.True(attempts.Succeeded);
+        Assert.InRange(attempts.Value!.Count, 1, 32);
+    }
+
     [Fact]
     public void IdempotencyRetentionMustCoverResourceLifetimes()
     {
@@ -385,7 +436,7 @@ public sealed class InMemoryEphemeralRendezvousStoreTests
         StoreResult<int> revoked = fixture.Store.RevokePrincipal(command.Listing.OwnerSubject, TimeSpan.FromMinutes(1));
 
         Assert.True(revoked.Succeeded);
-        Assert.Equal(2, revoked.Value);
+        Assert.Equal(4, revoked.Value);
         Assert.Equal(StoreResultCode.NotFound, fixture.Store.GetListing(listing.Definition.ListingId, false).Code);
         Assert.Equal(StoreResultCode.NotFound, fixture.Store.BindAttemptEndpoint(new(
             attempt.MediationHandle,