Merge pull request 'Release: the proxy hop count is set in Settings → Config' (#221) from dev into main

README.md

@@ -75,7 +75,7 @@ Everything is optional. Set these in the environment or in a `.env` file beside
 | Variable | When | What it does |
 |----------|------|--------------|
 | `BASE_URL` | Behind a proxy | The public URL, used in email links and SSO redirects |
-| `TRUSTED_PROXY_HOPS` | Behind a proxy | How many reverse proxies stand in front of Grimoire (default `1`; the compose file above sets `0` because it publishes the port directly). The client address and HTTPS are read from the proxy's headers by it |
+| `TRUSTED_PROXY_HOPS` | Rarely | The starting count of reverse proxies in front of Grimoire (default `1`; the compose file above sets `0` because it publishes the port directly). Check and change it in **Settings → Config → Reverse proxy**, which shows what each count reads for your own request; behind Cloudflare it is usually `2` |
 | `POSTGRES_PASSWORD` | Before the first start | The database password (defaults to `grimoire`; the database is reachable only inside the compose network). Postgres takes it once, when the volume is created |
 | `SECRET_KEY` | Rarely | A key you manage yourself, instead of the one Grimoire keeps. It wins over the kept key; remove it to go back |
 

docs/api-reference.md

@@ -281,6 +281,7 @@ These serve the plugin's hooks.
 | GET / PUT | `/api/admin/smtp` · POST `/api/admin/smtp/test` | SMTP config + test email |
 | GET | `/api/admin/logs` · `/api/admin/logs/stats` | Log entries + category counts |
 | GET / PUT | `/api/admin/base-url` | Get / set the public base URL |
+| GET / PUT | `/api/admin/proxy` | Get / set how many reverse proxies stand in front of Grimoire (`{"hops": n}`, or `null` for the environment's count), with what each count would read for this request |
 | GET / PUT | `/api/admin/db-maintenance` (+ `/health`, POST `/run`) | VACUUM schedule, health, manual run |
 | POST / GET / DELETE | `/api/admin/invitations` (+ `/:id`) | Create / list / revoke invite links |
 | GET / PUT | `/api/admin/backups` | Scheduled backups: destination, schedule and recent runs |

docs/configuration.md

@@ -14,7 +14,7 @@ Any variable marked *secret* can also be read from a file: set `<NAME>_FILE` to
 | `SECRET_KEY` *(secret)* | kept in `DATA_DIR` | Signs sessions and seals stored credentials. Unset, the instance makes its own on first start and keeps it in `DATA_DIR/secret_key`. Set it only to manage the key yourself; it wins over the kept one (see below) |
 | `DATA_DIR` | `/data` | Where the instance keeps its own `SECRET_KEY`. Mount a volume here |
 | `BASE_URL` | `http://localhost:5000` | Public URL, used in email links and OIDC redirects |
-| `TRUSTED_PROXY_HOPS` | `1` | How many reverse proxies stand in front of Grimoire. The client address and the scheme are read that many entries in from the right of `X-Forwarded-For` and `X-Forwarded-Proto`; `0` ignores both headers. See [Behind a reverse proxy](#behind-a-reverse-proxy) |
+| `TRUSTED_PROXY_HOPS` | `1` | The starting count of reverse proxies in front of Grimoire. **Settings → Config → Reverse proxy** is where the count is checked and set, and a count saved there wins over this. The client address and the scheme are read that many entries in from the right of `X-Forwarded-For` and `X-Forwarded-Proto`; `0` ignores both headers. See [Behind a reverse proxy](#behind-a-reverse-proxy) |
 | `LOG_LEVEL` | `INFO` | `DEBUG`, `INFO`, `WARNING` or `ERROR` |
 | `LOG_RETENTION_DAYS` | `90` | Days of app logs to keep |
 | `FASTEMBED_CACHE_DIR` | `/data/fastembed-cache` | Where the embedding model is stored after its first download |
@@ -95,7 +95,11 @@ Back up the database with **Settings → Data → Scheduled backups** ([Backups]
 
 ## Behind a reverse proxy
 
-Grimoire doesn't terminate TLS. Put it behind Nginx, Traefik or Caddy, forward to port 5000, and keep port 5000 off the internet. Set `BASE_URL`, and `TRUSTED_PROXY_HOPS` to the number of proxies a request passes through (one proxy is `1`, the default; Cloudflare in front of Traefik is `2`).
+Grimoire doesn't terminate TLS. Put it behind Nginx, Traefik or Caddy, forward to port 5000, and keep port 5000 off the internet. Set `BASE_URL`, then set the proxy count to the number of proxies a request passes through: one proxy is `1`, the default; Cloudflare's proxied DNS in front of your own proxy is `2`.
+
+**Settings → Config → Reverse proxy** sets the count and checks it against your own request. It shows the address Grimoire reads you as, and what each count from 0 to 3 would read. Pick the count that shows your own address. When a request comes through Cloudflare, the section names the count that reads the address Cloudflare reports, with a button that sets it. `TRUSTED_PROXY_HOPS` in the environment is only the starting value: a count saved in Settings wins, and **Use the environment's** goes back to it.
+
+A count that is too low makes every visitor read as the proxy, so they share one sign-in rate limit and a few bad sign-ins block everyone. The "too many attempts" message says so and points here. The block on sign-ins lifts after a minute; an admin who is already signed in can fix the count at once.
 
 ```nginx
 location / {
@@ -110,7 +114,7 @@ location / {
 }
 ```
 
-Each proxy appends its entry to `X-Forwarded-For` and `X-Forwarded-Proto`, so Grimoire reads the entry `TRUSTED_PROXY_HOPS` in from the right: the one your own proxy wrote. Whatever a client puts to the left of it is ignored. A header with fewer entries than that (a LAN road with one proxy beside a Cloudflare road with two) is read at its leftmost entry, the one the first proxy wrote.
+Each proxy appends its entry to `X-Forwarded-For` and `X-Forwarded-Proto`, so Grimoire reads the entry that many in from the right: the one your own proxy wrote. Whatever a client puts to the left of it is ignored. A header with fewer entries than that (a LAN road with one proxy beside a Cloudflare road with two) is read at its leftmost entry, the one the first proxy wrote.
 
 When that entry says `https`, the session cookie is marked `Secure` and the response carries `Strict-Transport-Security: max-age=31536000`. Over plain HTTP neither is sent, and Grimoire never redirects to HTTPS, so a LAN install keeps working.
 
@@ -119,7 +123,7 @@ A hop count higher than the real number of proxies lets a client choose its own
 ## Security checklist
 
 - **Keep the key.** Forge tokens and the backup destination's S3 secret are sealed under a key derived from `SECRET_KEY`, so a copy of the database alone can't read them. Unset, the instance makes a random key and keeps it in `/data/secret_key`, readable by its owner only; keep that volume. If the key changes (say, a restore onto an instance with a different key), Settings marks those credentials and asks for them again; nothing else breaks. The app warns at startup when `SECRET_KEY` is a public placeholder or `/data` is not a mounted volume, and refuses to start with a placeholder key (`dev-secret-change-me`, `change-me-in-production`).
-- **`TRUSTED_PROXY_HOPS`** matches the number of proxies in front of Grimoire, so rate limits and the audit log see the real client and the cookie is `Secure` over HTTPS.
+- **The proxy count** (Settings → Config → Reverse proxy) matches the number of proxies in front of Grimoire, so rate limits and the audit log see the real client and the cookie is `Secure` over HTTPS. The section shows whether it does.
 - **Registration** is open only for the first account. Invite people, or open it briefly from Settings.
 - **Signing everyone else out**: changing a password ends that user's other sessions; Settings → Account has a button for it too.
 - **API keys** are per user, shown once, and can be read-only. Revoke any you no longer use under Settings → MCP Access.

docs/features.md

@@ -103,7 +103,7 @@ Email and password, plus optional OIDC single sign-on (Authentik, Keycloak, ...)
 | Integrations | SearXNG, git forge connections |
 | Data | Export, backup and restore, scheduled backups (admin) |
 | MCP Access | API keys and the command to connect Claude |
-| Config (admin) | What's running, application URL, plugin marketplace, database maintenance, SMTP, forge webhook |
+| Config (admin) | What's running, reverse proxy count (checked against your own request), application URL, plugin marketplace, database maintenance, SMTP, forge webhook |
 | Shared areas (admin) | The canonical areas systems map to |
 | Platforms (admin) | The platform catalogue family canon is grouped by |
 | Users (admin) | Registration, invites, users |

frontend/src/components/ReverseProxySettings.vue

@@ -0,0 +1,309 @@
+<script setup lang="ts">
+import { computed, onMounted, ref } from "vue";
+import { apiGet, apiPut, apiErrorMessage } from "@/api/client";
+import { useToastStore } from "@/stores/toast";
+
+/**
+ * How many reverse proxies stand in front of Grimoire, checked against the
+ * admin's own request.
+ *
+ * Each proxy appends to X-Forwarded-For, and Grimoire reads the entry this many
+ * in from the right as the visitor's address. Every sign-in rate limit and
+ * audit line keys on that address, and the scheme read the same way decides
+ * whether the session cookie is Secure. Too low a count makes every visitor
+ * read as the proxy, so they share one rate limit and one bad sign-in run
+ * blocks everyone. Behind Cloudflare's proxied DNS the usual count is 2.
+ */
+interface ReadoutRow { hops: number; client: string; https: boolean }
+interface Readout {
+  peer: string;
+  forwarded_for: string[];
+  forwarded_proto: string[];
+  cloudflare: boolean;
+  cloudflare_client: string | null;
+  rows: ReadoutRow[];
+  suggested: number | null;
+}
+interface ProxyConfig {
+  hops: number;
+  source: "setting" | "env" | "default";
+  env_hops: number;
+  max_hops: number;
+  readout: Readout;
+}
+
+const toast = useToastStore();
+const config = ref<ProxyConfig | null>(null);
+const loadError = ref("");
+const draft = ref<number>(1);
+const saving = ref(false);
+const saved = ref(false);
+
+async function load() {
+  loadError.value = "";
+  try {
+    config.value = await apiGet<ProxyConfig>("/api/admin/proxy");
+    draft.value = config.value.hops;
+  } catch (e) {
+    loadError.value = apiErrorMessage(e, "The proxy settings could not be loaded.");
+  }
+}
+
+async function save(hops: number | null) {
+  saving.value = true;
+  saved.value = false;
+  try {
+    config.value = await apiPut<ProxyConfig>("/api/admin/proxy", { hops });
+    draft.value = config.value.hops;
+    saved.value = true;
+    setTimeout(() => (saved.value = false), 2000);
+  } catch (e) {
+    toast.show(apiErrorMessage(e, "Failed to save the proxy count"), "error");
+  } finally {
+    saving.value = false;
+  }
+}
+
+const readout = computed(() => config.value?.readout ?? null);
+const inForce = computed(() => readout.value?.rows.find((r) => r.hops === config.value?.hops) ?? null);
+
+// The verdict that leads the section. A Cloudflare request names the count to
+// set, since Cloudflare reports the visitor's address; any other road can only
+// show the address read and let the admin judge whether it is theirs.
+const verdict = computed<"set-suggested" | "cloudflare-unmatched" | "check" | null>(() => {
+  const r = readout.value;
+  if (!r || !config.value) return null;
+  if (r.cloudflare && r.suggested !== null && r.suggested !== config.value.hops) return "set-suggested";
+  if (r.cloudflare && r.suggested === null) return "cloudflare-unmatched";
+  return "check";
+});
+
+const sourceLabel = computed(() => {
+  const c = config.value;
+  if (!c) return "";
+  if (c.source === "setting") return "Saved here.";
+  if (c.source === "env") return `From TRUSTED_PROXY_HOPS in the environment (${c.env_hops}).`;
+  return "The default.";
+});
+
+const draftValid = computed(() =>
+  Number.isInteger(draft.value) && draft.value >= 0 && draft.value <= (config.value?.max_hops ?? 5),
+);
+
+onMounted(load);
+</script>
+
+<template>
+  <div class="proxy-settings">
+    <p v-if="loadError" class="error-msg">
+      {{ loadError }}
+      <button type="button" class="btn-ghost btn-compact" @click="load">Try again</button>
+    </p>
+    <p v-else-if="!config" class="state-msg">Reading this request&hellip;</p>
+
+    <template v-else-if="readout">
+      <div v-if="verdict === 'set-suggested'" class="proxy-warning" role="alert">
+        <p class="proxy-warning-title">Set the proxy count to {{ readout.suggested }}</p>
+        <p class="proxy-warning-body">
+          This request came through Cloudflare, which reports your address as
+          <code>{{ readout.cloudflare_client }}</code>. At {{ config.hops }}, Grimoire reads
+          <code>{{ inForce?.client }}</code> instead, so visitors share Cloudflare's addresses
+          and one sign-in limit.
+        </p>
+        <button type="button" class="btn-primary" :disabled="saving" @click="save(readout.suggested)">
+          Use {{ readout.suggested }}
+        </button>
+      </div>
+      <div v-else-if="verdict === 'cloudflare-unmatched'" class="proxy-warning" role="alert">
+        <p class="proxy-warning-title">This request came through Cloudflare</p>
+        <p class="proxy-warning-body">
+          No count reads the address Cloudflare reports for you. Check the forwarding chain below,
+          and that your own proxy passes Cloudflare's <code>X-Forwarded-For</code> on.
+        </p>
+      </div>
+      <p v-else class="proxy-verdict">
+        Grimoire reads this request as coming from <code>{{ inForce?.client || "an unknown address" }}</code>
+        <template v-if="inForce?.https"> over HTTPS</template>. If that is your address, the count
+        is right. If it is your proxy's, raise the count.
+      </p>
+
+      <div class="field proxy-field">
+        <label for="proxy-hops">Proxies in front of Grimoire</label>
+        <div class="proxy-input-row">
+          <input
+            id="proxy-hops"
+            v-model.number="draft"
+            type="number"
+            min="0"
+            :max="config.max_hops"
+            step="1"
+            class="fs-input input proxy-hops-input"
+          />
+          <button
+            type="button"
+            class="btn-primary"
+            :disabled="saving || !draftValid || draft === config.hops"
+            @click="save(draft)"
+          >
+            {{ saving ? "Saving..." : "Save" }}
+          </button>
+          <button
+            v-if="config.source === 'setting'"
+            type="button"
+            class="btn-ghost"
+            :disabled="saving"
+            @click="save(null)"
+          >
+            Use the environment's ({{ config.env_hops }})
+          </button>
+          <span v-if="saved" class="saved-msg">Saved. It applies to the next request.</span>
+        </div>
+        <p class="field-hint">
+          {{ sourceLabel }} One proxy (Traefik, Nginx, Caddy) is 1. Cloudflare in front of your own
+          proxy is 2. 0 ignores the forwarding headers and uses the connecting address.
+        </p>
+      </div>
+
+      <table class="proxy-table">
+        <caption>What each count makes of this request</caption>
+        <thead>
+          <tr><th class="num">Count</th><th>Reads you as</th><th>HTTPS</th><th></th></tr>
+        </thead>
+        <tbody>
+          <tr
+            v-for="row in readout.rows"
+            :key="row.hops"
+            :class="{ 'proxy-row-current': row.hops === config.hops }"
+          >
+            <td class="num">{{ row.hops }}</td>
+            <td><code>{{ row.client || "unknown" }}</code></td>
+            <td>{{ row.https ? "yes" : "no" }}</td>
+            <td class="proxy-row-tags">
+              <span v-if="row.hops === config.hops" class="proxy-tag">in force</span>
+              <span v-if="row.hops === readout.suggested && row.hops !== config.hops" class="proxy-tag proxy-tag-suggested">
+                suggested
+              </span>
+            </td>
+          </tr>
+        </tbody>
+      </table>
+
+      <dl class="proxy-chain">
+        <dt>Connecting address</dt>
+        <dd><code>{{ readout.peer || "unknown" }}</code></dd>
+        <dt>X-Forwarded-For</dt>
+        <dd v-if="readout.forwarded_for.length"><code>{{ readout.forwarded_for.join(", ") }}</code></dd>
+        <dd v-else class="proxy-absent">not sent</dd>
+        <dt>X-Forwarded-Proto</dt>
+        <dd v-if="readout.forwarded_proto.length"><code>{{ readout.forwarded_proto.join(", ") }}</code></dd>
+        <dd v-else class="proxy-absent">not sent</dd>
+      </dl>
+    </template>
+  </div>
+</template>
+
+<style scoped>
+.proxy-warning {
+  margin-bottom: var(--fs-space-4);
+  padding: var(--fs-space-3);
+  border: 1px solid var(--fs-warning);
+  border-radius: var(--fs-radius-md);
+  background: color-mix(in srgb, var(--fs-warning) 12%, var(--fs-surface-raised));
+}
+.proxy-warning-title {
+  margin: 0 0 var(--fs-space-2);
+  font-weight: 600;
+  color: var(--fs-warning-fg);
+}
+.proxy-warning-body {
+  margin: 0 0 var(--fs-space-3);
+  font-size: var(--fs-size-body-sm);
+  color: var(--fs-text-primary);
+}
+.proxy-verdict {
+  margin: 0 0 var(--fs-space-4);
+  font-size: var(--fs-size-body-sm);
+  color: var(--fs-text-primary);
+}
+.proxy-field {
+  margin-bottom: var(--fs-space-4);
+}
+.proxy-input-row {
+  display: flex;
+  align-items: center;
+  gap: var(--fs-space-3);
+  flex-wrap: wrap;
+}
+.proxy-hops-input {
+  width: 5rem;
+}
+.proxy-table {
+  width: 100%;
+  max-width: 560px;
+  border-collapse: collapse;
+  font-size: var(--fs-size-body-sm);
+  margin-bottom: var(--fs-space-4);
+}
+.proxy-table caption {
+  text-align: left;
+  font-size: var(--fs-size-label);
+  color: var(--fs-text-secondary);
+  margin-bottom: var(--fs-space-2);
+}
+.proxy-table th,
+.proxy-table td {
+  text-align: left;
+  padding: var(--fs-space-1) var(--fs-space-3);
+  border-bottom: 1px solid var(--fs-border-color);
+}
+.proxy-table th {
+  font-size: var(--fs-size-tiny);
+  text-transform: uppercase;
+  letter-spacing: 0.04em;
+  color: var(--fs-text-tertiary);
+  font-weight: 500;
+}
+.proxy-table .num {
+  text-align: right;
+  font-variant-numeric: tabular-nums;
+  width: 4rem;
+}
+.proxy-row-current td {
+  background: var(--fs-surface-hover);
+  font-weight: 600;
+}
+.proxy-row-tags {
+  white-space: nowrap;
+}
+.proxy-tag {
+  display: inline-block;
+  padding: 0 var(--fs-space-2);
+  border-radius: var(--fs-radius-pill);
+  font-size: var(--fs-size-tiny);
+  font-weight: 500;
+  color: var(--fs-text-secondary);
+  border: 1px solid var(--fs-border-active);
+}
+.proxy-tag-suggested {
+  color: var(--fs-warning-fg);
+  border-color: var(--fs-warning);
+}
+.proxy-chain {
+  display: grid;
+  grid-template-columns: max-content 1fr;
+  gap: var(--fs-space-1) var(--fs-space-4);
+  margin: 0;
+  font-size: var(--fs-size-body-sm);
+}
+.proxy-chain dt {
+  color: var(--fs-text-secondary);
+}
+.proxy-chain dd {
+  margin: 0;
+  overflow-wrap: anywhere;
+}
+.proxy-absent {
+  font-style: italic;
+  color: var(--fs-text-tertiary);
+}
+</style>

frontend/src/views/SettingsView.vue

@@ -9,6 +9,7 @@ import { apiGet, apiPost, apiPut, apiDelete, listGroups, createGroup, deleteGrou
 import type { User } from "@/types/auth";
 import PaginationBar from "@/components/PaginationBar.vue";
 import MomentsSettings from "@/components/MomentsSettings.vue";
+import ReverseProxySettings from "@/components/ReverseProxySettings.vue";
 import ReplyShapesSettings from "@/components/ReplyShapesSettings.vue";
 import BackupScheduleSettings from "@/components/BackupScheduleSettings.vue";
 import RestoreBackupDialog from "@/components/RestoreBackupDialog.vue";
@@ -2664,6 +2665,16 @@ async function deleteUser(userId: number) {
         <div v-else class="empty-msg">Nothing asked yet.</div>
       </section>
 
+      <section class="settings-section full-width">
+        <h2>Reverse proxy</h2>
+        <p class="section-desc">
+          How many proxies a request passes through before it reaches Grimoire. Sign-in rate
+          limits and the audit log key on the visitor's address, read through this count; if it
+          is too low, every visitor reads as the proxy and one run of bad sign-ins blocks everyone.
+        </p>
+        <ReverseProxySettings />
+      </section>
+
       <section class="settings-section full-width">
         <h2>Application URL</h2>
         <p class="section-desc">

src/grimoire/app.py

@@ -85,9 +85,9 @@ def create_app() -> Quart:
 
     if os.environ.get("TRUST_PROXY_HEADERS") and not os.environ.get("TRUSTED_PROXY_HOPS"):
         logger.warning(
-            "TRUST_PROXY_HEADERS is replaced by TRUSTED_PROXY_HOPS (now %d). Set "
+            "TRUST_PROXY_HEADERS is not used (the starting proxy hop count is %d). "
-            "TRUSTED_PROXY_HOPS to the number of proxies in front of Grimoire and "
+            "Remove it; set the count in Settings → Config, or TRUSTED_PROXY_HOPS "
-            "remove TRUST_PROXY_HEADERS.",
+            "to change the starting value.",
             Config.TRUSTED_PROXY_HOPS,
         )
 
@@ -202,6 +202,14 @@ def create_app() -> Quart:
         start_notification_loop()
         start_auth_token_retention_loop()
 
+        # The proxy hop count saved in Settings decides every request's client
+        # address, so it is loaded before serving, under a deadline (a failed
+        # or slow read leaves the environment's count in force), and re-read
+        # on an interval so a save in another worker reaches this one.
+        from grimoire.services import proxy_settings
+        await proxy_settings.load_at_startup()
+        proxy_settings.start_refresh_loop()
+
         # Write down any shipped default that moved in this release.
         #
         # INLINE AND AWAITED, deliberately, against the instinct the block

src/grimoire/config.py

@@ -124,8 +124,14 @@ class Config:
     BASE_URL: str = os.environ.get("BASE_URL", "http://localhost:5000").rstrip("/")
     # How many reverse proxies stand in front of the app; the client address
     # and scheme are read that many entries in from the right of the
-    # forwarding headers (grimoire/proxy.py). 0 trusts no proxy.
+    # forwarding headers (grimoire/proxy.py). 0 trusts no proxy. This is the
+    # install's starting value: a count saved in Settings → Config wins over
+    # it (services/proxy_settings.py).
     TRUSTED_PROXY_HOPS: int = _trusted_proxy_hops()
+    TRUSTED_PROXY_HOPS_FROM_ENV: bool = bool(
+        os.environ.get("TRUSTED_PROXY_HOPS", "").strip()
+        or os.environ.get("TRUST_PROXY_HEADERS", "").strip()
+    )
 
     # Git URL of the repo that ships this Grimoire plugin. There is one correct
     # value per deployment (the repo serving the plugin), so it's a config

src/grimoire/proxy.py

@@ -7,9 +7,10 @@ X-Forwarded-Proto, and each proxy on the road APPENDS its entry, so only the
 right-hand end of either header was written by a proxy we trust. Anything to
 the left of that is whatever the client chose to send.
 
-`TRUSTED_PROXY_HOPS` says how many proxies stand in front of the app (default
+The hop count says how many proxies stand in front of the app. An admin sets
-1). The entry read is that many in from the right. Zero trusts no proxy: the
+it in Settings → Config; until they do, it is `TRUSTED_PROXY_HOPS` from the
-headers are ignored and the socket peer is the client.
+environment (default 1). The entry read is that many in from the right. Zero
+trusts no proxy: the headers are ignored and the socket peer is the client.
 
 Never read X-Forwarded-For or X-Forwarded-Proto anywhere else. The client
 address keys the rate limits and the audit log, and the scheme decides the
@@ -43,10 +44,36 @@ def trusted_entry(header: str, hops: int) -> str | None:
     return entries[-min(hops, len(entries))]
 
 
-def _forwarded(name: str) -> str | None:
+# The count saved in Settings, or None when none is saved. Held here because
+# every request reads it and the read is synchronous; services/proxy_settings
+# loads it at startup, refreshes it on an interval in every worker, and sets it
+# at once in the worker that saved a new one.
+_saved_hops: int | None = None
+
+
+def set_saved_hops(hops: int | None) -> None:
+    global _saved_hops
+    _saved_hops = hops
+
+
+def saved_hops_in_force() -> int | None:
+    """The count saved in Settings that this worker holds, or None."""
+    return _saved_hops
+
+
+def trusted_hops() -> int:
+    """The hop count in force: the one saved in Settings, else the env's."""
+    return Config.TRUSTED_PROXY_HOPS if _saved_hops is None else _saved_hops
+
+
+def _chain(name: str) -> str:
     # Joined, because a header sent twice arrives as two values, and each
     # proxy's append may land on either one.
-    return trusted_entry(",".join(request.headers.getlist(name)), Config.TRUSTED_PROXY_HOPS)
+    return ",".join(request.headers.getlist(name))
+
+
+def _forwarded(name: str) -> str | None:
+    return trusted_entry(_chain(name), trusted_hops())
 
 
 def client_ip() -> str:
@@ -78,3 +105,60 @@ def apply_https_headers(response) -> None:
     HTTPS; plain HTTP is a supported way to run it."""
     if is_https():
         response.headers.setdefault("Strict-Transport-Security", HSTS_VALUE)
+
+
+# Cloudflare writes the visitor's address here on every request it proxies.
+# Read only to SUGGEST a hop count in the readout, never to decide one: a
+# client that reaches the app without Cloudflare can send it too.
+CLOUDFLARE_CLIENT_HEADER = "CF-Connecting-IP"
+CLOUDFLARE_MARKERS = (CLOUDFLARE_CLIENT_HEADER, "CF-Ray")
+READOUT_HOPS = range(0, 4)
+MAX_HOPS = 5
+
+
+def readout(peer: str, forwarded_for: str, forwarded_proto: str,
+            cloudflare_client: str | None, scheme: str = "http") -> dict:
+    """What each hop count would make of one request, so an admin can pick
+    the count that shows their own address. Pure: the request's parts come in
+    as arguments.
+
+    `suggested` is the smallest count that reads the address Cloudflare
+    reports, when the request came through Cloudflare; otherwise None, since
+    only the admin knows which address is theirs.
+    """
+    def read(hops: int) -> dict:
+        address = trusted_entry(forwarded_for, hops) or peer
+        proto = trusted_entry(forwarded_proto, hops)
+        https = scheme == "https" or (proto or "").lower() == "https"
+        return {"hops": hops, "client": address, "https": https}
+
+    suggested = None
+    if cloudflare_client:
+        suggested = next(
+            (h for h in range(1, MAX_HOPS + 1)
+             if trusted_entry(forwarded_for, h) == cloudflare_client),
+            None,
+        )
+    return {
+        "peer": peer,
+        "forwarded_for": [p.strip() for p in forwarded_for.split(",") if p.strip()],
+        "forwarded_proto": [p.strip() for p in forwarded_proto.split(",") if p.strip()],
+        "cloudflare": cloudflare_client is not None,
+        "cloudflare_client": cloudflare_client,
+        "rows": [read(h) for h in READOUT_HOPS],
+        "suggested": suggested,
+    }
+
+
+def request_readout() -> dict:
+    """`readout` for the current request."""
+    cloudflare = request.headers.get(CLOUDFLARE_CLIENT_HEADER)
+    if cloudflare is None and request.headers.get("CF-Ray"):
+        cloudflare = ""
+    return readout(
+        request.remote_addr or "",
+        _chain("X-Forwarded-For"),
+        _chain("X-Forwarded-Proto"),
+        cloudflare.strip() if cloudflare is not None else None,
+        request.scheme,
+    )

src/grimoire/rate_limit.py

@@ -2,15 +2,23 @@
 
 IMPORTANT — deployment note:
   Rate limit counters are stored in memory and are lost on process restart.
-  The bucket key is the client address from grimoire/proxy.py, read by
+  The bucket key is the client address from grimoire/proxy.py, read by the
-  TRUSTED_PROXY_HOPS. A hop count that is too low keys every caller on the
+  proxy hop count (Settings → Config). A count that is too low keys every
-  proxy's address, so they all share one bucket.
+  caller on the proxy's address, so they all share one bucket.
 """
 
 import asyncio
 import time
 from collections import defaultdict
 
+# Said beside every "too many attempts" reply, because the one case a person
+# can't diagnose on their own is everybody being blocked at once: the proxy
+# count is too low, so every visitor reads as the proxy and shares one bucket.
+SHARED_ADDRESS_HINT = (
+    "If everyone is being blocked, an admin should check the reverse proxy count "
+    "in Settings → Config: every visitor may be reading as the proxy's address."
+)
+
 _buckets: dict[str, list[float]] = defaultdict(list)
 _lock = asyncio.Lock()
 

src/grimoire/routes/admin.py

@@ -3,8 +3,11 @@ import json
 
 from quart import Blueprint, Response, g, jsonify, request
 
+from grimoire import proxy
 from grimoire.auth import admin_required, login_required, get_current_user_id
+from grimoire.config import Config
 from grimoire.proxy import client_ip
+from grimoire.services import proxy_settings
 from grimoire.services.auth import (
     create_invitation,
     delete_user,
@@ -260,7 +263,6 @@ async def test_smtp():
 @admin_bp.route("/forge-webhook", methods=["GET"])
 @admin_required
 async def get_forge_webhook_settings():
-    from grimoire.config import Config
     from grimoire.routes.webhooks import FORGE_WEBHOOK_SECRET_KEY
 
     webhook_secret = (
@@ -346,6 +348,44 @@ async def update_base_url():
     return jsonify({"status": "ok"})
 
 
+def _proxy_payload() -> dict:
+    return {
+        "hops": proxy.trusted_hops(),
+        "source": proxy_settings.source(),
+        "env_hops": Config.TRUSTED_PROXY_HOPS,
+        "max_hops": proxy.MAX_HOPS,
+        "readout": proxy.request_readout(),
+    }
+
+
+@admin_bp.route("/proxy", methods=["GET"])
+@admin_required
+async def get_proxy_setting():
+    """The hop count in force, where it came from, and what each count would
+    make of the admin's own request."""
+    return jsonify(_proxy_payload())
+
+
+@admin_bp.route("/proxy", methods=["PUT"])
+@admin_required
+async def update_proxy_setting():
+    """Save the hop count, or `{"hops": null}` to go back to the environment's.
+    It applies to the next request."""
+    data = await request.get_json() or {}
+    raw = data.get("hops")
+    hops = None if raw is None else proxy_settings.parse_hops(raw)
+    if raw is not None and hops is None:
+        return jsonify({"error": f"The proxy count must be a whole number from 0 to {proxy.MAX_HOPS}."}), 400
+    before = proxy.trusted_hops()
+    await proxy_settings.save_hops(hops)
+    uid = get_current_user_id()
+    await log_audit(
+        "proxy_hops_config", user_id=uid, username=g.user.username, ip_address=client_ip(),
+        details={"before": before, "after": proxy.trusted_hops(), "saved": hops},
+    )
+    return jsonify(_proxy_payload())
+
+
 @admin_bp.route("/db-maintenance", methods=["GET"])
 @admin_required
 async def get_db_maintenance():

src/grimoire/routes/auth.py

@@ -9,7 +9,7 @@ from quart import Blueprint, g, jsonify, redirect, request, session
 from grimoire.auth import login_required, get_current_user_id
 from grimoire.config import Config
 from grimoire.proxy import client_ip
-from grimoire.rate_limit import is_rate_limited
+from grimoire.rate_limit import SHARED_ADDRESS_HINT, is_rate_limited
 from grimoire.services.auth import (
     authenticate,
     change_password,
@@ -49,7 +49,7 @@ async def register():
     if not Config.LOCAL_AUTH_ENABLED:
         return jsonify({"error": "Local authentication is disabled. Please use SSO."}), 403
     if await is_rate_limited(f"register:{client_ip()}", max_requests=5, window_seconds=300):
-        return jsonify({"error": "Too many registration attempts. Try again later."}), 429
+        return jsonify({"error": f"Too many registration attempts. Try again later. {SHARED_ADDRESS_HINT}"}), 429
     if not await is_registration_open():
         return jsonify({"error": "Registration is closed"}), 403
 
@@ -79,7 +79,7 @@ async def login():
     if not Config.LOCAL_AUTH_ENABLED:
         return jsonify({"error": "Local authentication is disabled. Please use SSO."}), 403
     if await is_rate_limited(f"login:{client_ip()}", max_requests=10, window_seconds=60):
-        return jsonify({"error": "Too many login attempts. Try again later."}), 429
+        return jsonify({"error": f"Too many login attempts. Try again later. {SHARED_ADDRESS_HINT}"}), 429
     data = await request.get_json()
     username = (data.get("username") or "").strip()
     password = data.get("password") or ""
@@ -235,7 +235,7 @@ async def forgot_password():
 @auth_bp.route("/reset-password", methods=["POST"])
 async def reset_password():
     if await is_rate_limited(f"reset:{client_ip()}", max_requests=10, window_seconds=60):
-        return jsonify({"error": "Too many attempts. Try again later."}), 429
+        return jsonify({"error": f"Too many attempts. Try again later. {SHARED_ADDRESS_HINT}"}), 429
     data = await request.get_json()
     token = (data.get("token") or "").strip()
     new_password = data.get("new_password") or ""

src/grimoire/services/proxy_settings.py

@@ -0,0 +1,129 @@
+"""The reverse-proxy hop count an admin saves in Settings → Config.
+
+How many proxies stand in front of the app decides which address every rate
+limit and audit line sees, and whether a request counts as HTTPS
+(grimoire/proxy.py). Behind Cloudflare's proxied DNS the right count is 2; at
+the default of 1 every visitor reads as a Cloudflare edge address and they
+share one sign-in rate limit. So the count is set where an admin can find it
+and check it against their own request, not only in the environment.
+
+Precedence: the saved count, then `TRUSTED_PROXY_HOPS` from the environment,
+then 1. Saving None removes the saved count, so the environment's applies
+again.
+
+It is one instance-wide value, kept on the first admin account like the other
+instance settings. Every worker holds it in proxy.py, loads it at startup and
+re-reads it every REFRESH_SECONDS, so a save in one worker reaches the others
+within that interval; the worker that saved applies it at once.
+"""
+from __future__ import annotations
+
+import asyncio
+import logging
+
+from sqlalchemy import delete, select
+
+from grimoire import proxy
+from grimoire.config import Config
+from grimoire.models import async_session
+from grimoire.models.setting import Setting
+from grimoire.models.user import User
+
+logger = logging.getLogger(__name__)
+
+SETTING_KEY = "trusted_proxy_hops"
+REFRESH_SECONDS = 30
+# The load at startup runs inside the lifespan hook, and a hook that does not
+# return is a worker that never serves (db_maintenance_scheduler explains the
+# outage that taught this). One indexed row answers in milliseconds, so the
+# deadline only fires when the database is already in trouble.
+STARTUP_READ_TIMEOUT = 3.0
+
+
+def parse_hops(raw) -> int | None:
+    """A hop count from 0 to proxy.MAX_HOPS, or None for anything else. A
+    bool is refused, though Python counts it as an int."""
+    if isinstance(raw, bool):
+        return None
+    if isinstance(raw, str):
+        raw = raw.strip()
+        if not raw.isdigit():
+            return None
+        raw = int(raw)
+    if not isinstance(raw, int) or not 0 <= raw <= proxy.MAX_HOPS:
+        return None
+    return raw
+
+
+def _admin_rows():
+    return (
+        select(Setting)
+        .join(User, Setting.user_id == User.id)
+        .where(User.role == "admin", Setting.key == SETTING_KEY)
+    )
+
+
+async def saved_hops() -> int | None:
+    """The count saved in Settings, or None when there is none (or what is
+    stored can't be read as one)."""
+    async with async_session() as session:
+        row = (await session.execute(_admin_rows().order_by(Setting.user_id))).scalars().first()
+    return parse_hops(row.value) if row else None
+
+
+async def save_hops(hops: int | None) -> None:
+    """Save the count, or remove it with None. Any copy on another admin's
+    account goes too, so exactly one value is ever read back."""
+    async with async_session() as session:
+        admin_ids = select(User.id).where(User.role == "admin")
+        await session.execute(
+            delete(Setting).where(Setting.key == SETTING_KEY, Setting.user_id.in_(admin_ids))
+        )
+        if hops is not None:
+            first_admin = (
+                await session.execute(select(User.id).where(User.role == "admin").order_by(User.id))
+            ).scalars().first()
+            if first_admin is None:
+                raise ValueError("there is no admin account to keep the setting on")
+            session.add(Setting(user_id=first_admin, key=SETTING_KEY, value=str(hops)))
+        await session.commit()
+    proxy.set_saved_hops(hops)
+
+
+async def refresh() -> None:
+    """Load the saved count into this worker. A failed read keeps the value
+    it already had: an unreachable database must not switch the trust rule."""
+    try:
+        proxy.set_saved_hops(await saved_hops())
+    except Exception:
+        logger.debug("could not re-read the saved proxy hop count", exc_info=True)
+
+
+async def load_at_startup() -> None:
+    """`refresh`, bounded for the lifespan hook. On a timeout the environment's
+    count stays in force until the next refresh reaches the database."""
+    try:
+        await asyncio.wait_for(refresh(), timeout=STARTUP_READ_TIMEOUT)
+    except (TimeoutError, asyncio.TimeoutError):
+        logger.warning(
+            "reading the saved proxy hop count exceeded %.1fs; starting with %d "
+            "from the environment until the database answers",
+            STARTUP_READ_TIMEOUT, Config.TRUSTED_PROXY_HOPS,
+        )
+
+
+_refresh_task = None
+
+
+def start_refresh_loop() -> None:
+    global _refresh_task
+    if _refresh_task is None or _refresh_task.done():
+        from grimoire.services.background import start_periodic
+        _refresh_task = start_periodic(REFRESH_SECONDS, refresh, label="proxy_hops_refresh")
+
+
+def source() -> str:
+    """Where the count in force came from: "setting", "env" or "default"."""
+    if proxy.saved_hops_in_force() is not None:
+        return "setting"
+    return "env" if Config.TRUSTED_PROXY_HOPS_FROM_ENV else "default"

tests/test_integration_proxy_settings.py

@@ -0,0 +1,70 @@
+"""The saved proxy hop count against a real database.
+
+What only a real database shows: the count is read back after a save, saving
+leaves exactly one copy however many admins there are, saving None removes it,
+and a saved count reaches `client_ip()` through the worker's cache.
+"""
+import pytest
+from quart import Quart
+from sqlalchemy import select
+
+from grimoire import proxy
+from grimoire.config import Config
+from grimoire.models import async_session
+from grimoire.models.setting import Setting
+from grimoire.proxy import client_ip
+from grimoire.services import proxy_settings
+from tests.helpers import ensure_user
+
+pytestmark = [pytest.mark.integration, pytest.mark.usefixtures("_dispose_engine")]
+
+
+async def _copies() -> list[Setting]:
+    async with async_session() as s:
+        return list((await s.execute(
+            select(Setting).where(Setting.key == proxy_settings.SETTING_KEY)
+        )).scalars().all())
+
+
+@pytest.fixture
+async def two_admins():
+    async with async_session() as s:
+        first = await ensure_user(s, "proxy_hops_admin_a", role="admin")
+        second = await ensure_user(s, "proxy_hops_admin_b", role="admin")
+        await s.commit()
+        ids = (first.id, second.id)
+    yield ids
+    await proxy_settings.save_hops(None)
+    proxy.set_saved_hops(None)
+
+
+async def test_a_saved_count_reads_back_and_leaves_one_copy(two_admins):
+    # A stale copy on the second admin, as an older write path could leave.
+    async with async_session() as s:
+        s.add(Setting(user_id=two_admins[1], key=proxy_settings.SETTING_KEY, value="4"))
+        await s.commit()
+
+    await proxy_settings.save_hops(2)
+    assert await proxy_settings.saved_hops() == 2
+    copies = await _copies()
+    assert len(copies) == 1 and copies[0].value == "2"
+
+
+async def test_saving_none_removes_the_count(two_admins):
+    await proxy_settings.save_hops(3)
+    await proxy_settings.save_hops(None)
+    assert await proxy_settings.saved_hops() is None
+    assert await _copies() == []
+    assert proxy.saved_hops_in_force() is None
+
+
+async def test_a_saved_count_reaches_the_client_address(two_admins, monkeypatch):
+    monkeypatch.setattr(Config, "TRUSTED_PROXY_HOPS", 1)
+    await proxy_settings.save_hops(2)
+    proxy.set_saved_hops(None)          # as in another worker, before its refresh
+    await proxy_settings.refresh()
+
+    app = Quart(__name__)
+    headers = {"Remote-Addr": "10.0.0.5", "X-Forwarded-For": "203.0.113.7, 172.70.1.1"}
+    async with app.test_request_context("/", headers=headers):
+        assert client_ip() == "203.0.113.7"

tests/test_proxy_settings.py

@@ -0,0 +1,232 @@
+"""The reverse-proxy hop count an admin sets in Settings → Config.
+
+Behind Cloudflare's proxied DNS the right count is 2. At the default of 1,
+every visitor reads as a Cloudflare edge address and shares one sign-in rate
+limit, so a few bad sign-ins block everyone. The count is therefore saved where
+an admin can find it, beside a readout of what each count makes of their own
+request. Covered here:
+- the saved count wins over the environment's;
+- the readout picks out the Cloudflare road;
+- the admin route validates what it saves;
+- a "too many attempts" reply says where to look.
+"""
+import asyncio
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, patch
+
+import pytest
+from quart import Quart, g
+
+from grimoire import proxy
+from grimoire.config import Config
+from grimoire.proxy import client_ip, readout, request_readout, trusted_hops
+from grimoire.rate_limit import SHARED_ADDRESS_HINT
+from grimoire.services import proxy_settings
+
+VISITOR = "203.0.113.7"
+CLOUDFLARE_EDGE = "172.70.1.1"
+LAN_VISITOR = "192.168.1.20"
+TRAEFIK = "10.0.0.5"
+
+
+@pytest.fixture(autouse=True)
+def _no_saved_count():
+    proxy.set_saved_hops(None)
+    yield
+    proxy.set_saved_hops(None)
+
+
+def _context(headers: dict):
+    app = Quart(__name__)
+    return app.test_request_context("/", headers={"Remote-Addr": TRAEFIK, **headers})
+
+
+@pytest.mark.parametrize("raw, expected", [
+    (0, 0), (2, 2), (5, 5), ("3", 3), (" 1 ", 1),
+    (6, None), (-1, None), ("x", None), ("", None), (True, None), (1.5, None), (None, None),
+])
+def test_a_hop_count_is_a_whole_number_from_zero_to_five(raw, expected):
+    assert proxy_settings.parse_hops(raw) == expected
+
+
+def test_the_saved_count_wins_over_the_environments(monkeypatch):
+    monkeypatch.setattr(Config, "TRUSTED_PROXY_HOPS", 1)
+    assert trusted_hops() == 1
+    proxy.set_saved_hops(2)
+    assert trusted_hops() == 2
+    proxy.set_saved_hops(0)
+    assert trusted_hops() == 0, "a saved 0 is a count, not an absence"
+
+
+async def test_the_client_address_follows_a_saved_count(monkeypatch):
+    monkeypatch.setattr(Config, "TRUSTED_PROXY_HOPS", 1)
+    async with _context({"X-Forwarded-For": f"{VISITOR}, {CLOUDFLARE_EDGE}"}):
+        assert client_ip() == CLOUDFLARE_EDGE
+        proxy.set_saved_hops(2)
+        assert client_ip() == VISITOR
+
+
+@pytest.mark.parametrize("saved, from_env, expected", [
+    (2, False, "setting"), (2, True, "setting"), (None, True, "env"), (None, False, "default"),
+])
+def test_the_source_names_where_the_count_came_from(monkeypatch, saved, from_env, expected):
+    monkeypatch.setattr(Config, "TRUSTED_PROXY_HOPS_FROM_ENV", from_env)
+    proxy.set_saved_hops(saved)
+    assert proxy_settings.source() == expected
+
+
+def test_the_readout_suggests_the_count_that_reads_cloudflares_visitor():
+    out = readout(TRAEFIK, f"{VISITOR}, {CLOUDFLARE_EDGE}", "https, https", VISITOR)
+    by_hops = {row["hops"]: row for row in out["rows"]}
+    assert by_hops[0]["client"] == TRAEFIK
+    assert by_hops[1]["client"] == CLOUDFLARE_EDGE
+    assert by_hops[2]["client"] == VISITOR and by_hops[2]["https"] is True
+    assert out["cloudflare"] is True and out["suggested"] == 2
+    assert out["forwarded_for"] == [VISITOR, CLOUDFLARE_EDGE]
+
+
+def test_the_readout_suggests_nothing_off_cloudflare():
+    # Only the admin knows which address is theirs on a road with no
+    # Cloudflare header to compare against.
+    out = readout(TRAEFIK, LAN_VISITOR, "http", None)
+    assert out["cloudflare"] is False and out["suggested"] is None
+    assert [row["client"] for row in out["rows"]] == [TRAEFIK, LAN_VISITOR, LAN_VISITOR, LAN_VISITOR]
+    assert not any(row["https"] for row in out["rows"])
+
+
+def test_the_readout_rows_can_disagree():
+    # The guard above passes vacuously if every row reads the same address.
+    out = readout(TRAEFIK, f"{VISITOR}, {CLOUDFLARE_EDGE}", "", VISITOR)
+    assert len({row["client"] for row in out["rows"]}) == 3
+
+
+async def test_the_request_readout_reads_the_cloudflare_headers():
+    headers = {"X-Forwarded-For": f"{VISITOR}, {CLOUDFLARE_EDGE}", "CF-Connecting-IP": VISITOR}
+    async with _context(headers):
+        out = request_readout()
+    assert out["peer"] == TRAEFIK and out["cloudflare_client"] == VISITOR and out["suggested"] == 2
+
+    async with _context({"CF-Ray": "8a1b2c3d4e5f-LHR"}):
+        out = request_readout()
+    assert out["cloudflare"] is True and out["suggested"] is None
+
+
+async def test_a_failed_refresh_keeps_the_count_in_force():
+    proxy.set_saved_hops(2)
+    with patch.object(proxy_settings, "saved_hops", AsyncMock(side_effect=OSError("db down"))):
+        await proxy_settings.refresh()
+    assert trusted_hops() == 2
+
+
+async def test_a_hanging_startup_read_does_not_hold_up_the_boot(monkeypatch):
+    async def _never():
+        await asyncio.Event().wait()
+
+    monkeypatch.setattr(proxy_settings, "STARTUP_READ_TIMEOUT", 0.05)
+    with patch.object(proxy_settings, "refresh", _never), \
+         patch.object(proxy_settings.logger, "warning") as warn:
+        await asyncio.wait_for(proxy_settings.load_at_startup(), timeout=2)
+    assert warn.called
+
+
+def test_the_startup_read_has_a_deadline():
+    assert 0 < proxy_settings.STARTUP_READ_TIMEOUT < 60
+
+
+# ── the admin route ──────────────────────────────────────────────────────────
+
+
+async def _call(method: str, body=None):
+    from grimoire.app import create_app
+    from grimoire.routes import admin
+
+    app = create_app()
+    view = admin.get_proxy_setting if method == "GET" else admin.update_proxy_setting
+    async with app.test_request_context("/api/admin/proxy", method=method, json=body,
+                                        headers={"Remote-Addr": TRAEFIK}):
+        g.user = SimpleNamespace(id=1, username="admin", role="admin")
+        resp = await view.__wrapped__()
+    if isinstance(resp, tuple):
+        return resp[1], await resp[0].get_json()
+    return resp.status_code, await resp.get_json()
+
+
+async def _fake_save(hops):
+    proxy.set_saved_hops(hops)
+
+
+async def test_the_route_reports_the_count_its_source_and_the_readout(monkeypatch):
+    monkeypatch.setattr(Config, "TRUSTED_PROXY_HOPS", 1)
+    proxy.set_saved_hops(2)
+    status, body = await _call("GET")
+    assert status == 200
+    assert body["hops"] == 2 and body["source"] == "setting" and body["env_hops"] == 1
+    assert body["max_hops"] == proxy.MAX_HOPS
+    assert body["readout"]["peer"] == TRAEFIK and len(body["readout"]["rows"]) == 4
+
+
+async def test_saving_a_count_applies_it_and_audits_the_change(monkeypatch):
+    from grimoire.routes import admin
+
+    monkeypatch.setattr(Config, "TRUSTED_PROXY_HOPS", 1)
+    save = AsyncMock(side_effect=_fake_save)
+    audit = AsyncMock()
+    with patch.object(admin.proxy_settings, "save_hops", save), patch.object(admin, "log_audit", audit):
+        status, body = await _call("PUT", {"hops": 2})
+    assert status == 200 and body["hops"] == 2
+    save.assert_awaited_once_with(2)
+    details = audit.call_args.kwargs["details"]
+    assert details == {"before": 1, "after": 2, "saved": 2}
+
+
+async def test_saving_null_goes_back_to_the_environments_count(monkeypatch):
+    from grimoire.routes import admin
+
+    monkeypatch.setattr(Config, "TRUSTED_PROXY_HOPS", 1)
+    proxy.set_saved_hops(3)
+    save = AsyncMock(side_effect=_fake_save)
+    with patch.object(admin.proxy_settings, "save_hops", save), patch.object(admin, "log_audit", AsyncMock()):
+        status, body = await _call("PUT", {"hops": None})
+    assert status == 200 and body["hops"] == 1
+    save.assert_awaited_once_with(None)
+
+
+@pytest.mark.parametrize("bad", [6, -1, "two", True, 1.5])
+async def test_a_count_out_of_range_is_refused_and_nothing_is_saved(bad):
+    from grimoire.routes import admin
+
+    save = AsyncMock()
+    with patch.object(admin.proxy_settings, "save_hops", save):
+        status, body = await _call("PUT", {"hops": bad})
+    assert status == 400 and "0 to 5" in body["error"]
+    save.assert_not_awaited()
+
+
+@pytest.mark.parametrize("method", ["GET", "PUT"])
+async def test_the_route_is_for_admins_only(method):
+    from grimoire.app import create_app
+    from grimoire.routes import admin
+
+    view = admin.get_proxy_setting if method == "GET" else admin.update_proxy_setting
+    app = create_app()
+    async with app.test_request_context("/api/admin/proxy", method=method, json={"hops": 2}):
+        resp = await view()
+    assert resp[1] == 401
+
+
+# ── where a lockout shows up ─────────────────────────────────────────────────
+
+
+async def test_a_rate_limited_sign_in_says_where_an_admin_should_look(monkeypatch):
+    from grimoire.app import create_app
+    from grimoire.routes import auth
+
+    monkeypatch.setattr(Config, "LOCAL_AUTH_ENABLED", True)
+    app = create_app()
+    with patch.object(auth, "is_rate_limited", AsyncMock(return_value=True)):
+        async with app.test_request_context("/api/auth/login", method="POST", json={}):
+            resp, status = await auth.login()
+    body = await resp.get_json()
+    assert status == 429
+    assert SHARED_ADDRESS_HINT in body["error"]
+    assert "Settings → Config" in SHARED_ADDRESS_HINT