diff --git a/docs/TROUBLESHOOTING.md b/docs/TROUBLESHOOTING.md
index eaa7e5cebb..1a1102e057 100644
--- a/docs/TROUBLESHOOTING.md
+++ b/docs/TROUBLESHOOTING.md
@@ -58,9 +58,35 @@ screen for this instance and do not paste it into support requests or issue
 reports.
 
 ### Port change didn't take effect
-1. Check which service is running: `systemctl status pulse` (legacy installs may use `pulse-backend`).
-2. Verify environment override: `systemctl show pulse --property=Environment`.
-3. Docker: Ensure you updated the `-p` flag (e.g., `-p 8080:7655`).
+
+The web UI and API listen on `FRONTEND_PORT` (default `7655`). The deprecated
+`PORT` alias applies only when `FRONTEND_PORT` is unset; changing
+`frontendPort` in `system.json` has no effect. `PULSE_AGENT_INGEST_PORT` is a
+separate agent listener, not the web UI port. See
+[Port configuration](CONFIGURATION.md#common-overrides-environment-variables).
+
+- **Systemd / Proxmox LXC**: identify the active service with
+  `systemctl is-active pulse` (legacy installs may use `pulse-backend`). Inspect
+  only the port setting in its managed configuration locally. If you change a
+  unit or drop-in, run `sudo systemctl daemon-reload`, then restart the affected
+  service during a suitable maintenance window. For LXC, run these checks inside
+  the Pulse container, not on the Proxmox host.
+- **Docker / Compose**: distinguish the published host port from the listener
+  inside the container. With the default listener, `8080:7655` exposes the UI on
+  host port `8080`; changing the host port does not require `FRONTEND_PORT`.
+  In the repository's Compose file, `PULSE_PORT` controls this host-side mapping.
+  Save the mapping in your existing Compose project and apply it with
+  `docker compose up -d pulse`, keeping the same image and mounted data volume.
+  Restarting an existing container does not apply a new port mapping. For other
+  container managers, use their recreate/redeploy action while preserving the
+  data mount; do not delete the volume.
+- **Reverse proxy**: check its upstream port and the firewall separately. A
+  working agent connection on a split-port deployment does not prove that the
+  web UI is reachable.
+
+Do not post full service environments, `docker inspect` output or resolved
+`docker compose config` output: they can include passwords and tokens. Share
+only the relevant port numbers and a redacted error if help is needed.
 
 ### "Connection Refused"
 - Check if Pulse is running.
diff --git a/frontend-modern/public/docs/TROUBLESHOOTING.md b/frontend-modern/public/docs/TROUBLESHOOTING.md
index eaa7e5cebb..1a1102e057 100644
--- a/frontend-modern/public/docs/TROUBLESHOOTING.md
+++ b/frontend-modern/public/docs/TROUBLESHOOTING.md
@@ -58,9 +58,35 @@ screen for this instance and do not paste it into support requests or issue
 reports.
 
 ### Port change didn't take effect
-1. Check which service is running: `systemctl status pulse` (legacy installs may use `pulse-backend`).
-2. Verify environment override: `systemctl show pulse --property=Environment`.
-3. Docker: Ensure you updated the `-p` flag (e.g., `-p 8080:7655`).
+
+The web UI and API listen on `FRONTEND_PORT` (default `7655`). The deprecated
+`PORT` alias applies only when `FRONTEND_PORT` is unset; changing
+`frontendPort` in `system.json` has no effect. `PULSE_AGENT_INGEST_PORT` is a
+separate agent listener, not the web UI port. See
+[Port configuration](CONFIGURATION.md#common-overrides-environment-variables).
+
+- **Systemd / Proxmox LXC**: identify the active service with
+  `systemctl is-active pulse` (legacy installs may use `pulse-backend`). Inspect
+  only the port setting in its managed configuration locally. If you change a
+  unit or drop-in, run `sudo systemctl daemon-reload`, then restart the affected
+  service during a suitable maintenance window. For LXC, run these checks inside
+  the Pulse container, not on the Proxmox host.
+- **Docker / Compose**: distinguish the published host port from the listener
+  inside the container. With the default listener, `8080:7655` exposes the UI on
+  host port `8080`; changing the host port does not require `FRONTEND_PORT`.
+  In the repository's Compose file, `PULSE_PORT` controls this host-side mapping.
+  Save the mapping in your existing Compose project and apply it with
+  `docker compose up -d pulse`, keeping the same image and mounted data volume.
+  Restarting an existing container does not apply a new port mapping. For other
+  container managers, use their recreate/redeploy action while preserving the
+  data mount; do not delete the volume.
+- **Reverse proxy**: check its upstream port and the firewall separately. A
+  working agent connection on a split-port deployment does not prove that the
+  web UI is reachable.
+
+Do not post full service environments, `docker inspect` output or resolved
+`docker compose config` output: they can include passwords and tokens. Share
+only the relevant port numbers and a redacted error if help is needed.
 
 ### "Connection Refused"
 - Check if Pulse is running.
diff --git a/frontend-modern/src/utils/__tests__/docsLinks.test.ts b/frontend-modern/src/utils/__tests__/docsLinks.test.ts
index 46376c4b24..172e0345b4 100644
--- a/frontend-modern/src/utils/__tests__/docsLinks.test.ts
+++ b/frontend-modern/src/utils/__tests__/docsLinks.test.ts
@@ -149,6 +149,28 @@ describe('docsLinks', () => {
     expect(help).toContain('If installation never started Pulse');
   });
 
+  it('keeps port troubleshooting specific without exposing deployment credentials', () => {
+    const troubleshooting = readFileSync(path.join(repoRoot, 'docs', 'TROUBLESHOOTING.md'), 'utf8');
+    const ports = troubleshooting.split("### Port change didn't take effect")[1].split('\n### ')[0];
+
+    expect(ports).toContain('CONFIGURATION.md#common-overrides-environment-variables');
+    expect(ports).toContain('`PORT` alias applies only when `FRONTEND_PORT` is unset');
+    expect(ports).toContain('`frontendPort` in `system.json` has no effect');
+    expect(ports).toContain('separate agent listener, not the web UI port');
+    expect(ports).toContain('`systemctl is-active pulse`');
+    expect(ports).toContain('`sudo systemctl daemon-reload`');
+    expect(ports).toContain('inside\n  the Pulse container, not on the Proxmox host');
+    expect(ports).toContain('`docker compose up -d pulse`');
+    expect(ports).toContain('same image and mounted data volume');
+    expect(ports).toContain('Restarting an existing container does not apply a new port mapping');
+    expect(ports).toContain('do not delete the volume');
+    expect(ports).toContain('Do not post full service environments');
+    expect(ports).not.toContain('--property=Environment');
+    expect(ports).not.toMatch(
+      /`(?:sudo )?(?:systemctl (?:status|cat)|docker inspect|docker compose config)[^`]*`(?! output)/,
+    );
+  });
+
   it('keeps clone identity recovery separate from destructive OS or credential resets', () => {
     const troubleshooting = readFileSync(path.join(repoRoot, 'docs', 'TROUBLESHOOTING.md'), 'utf8');
     const agentGuide = readFileSync(path.join(repoRoot, 'docs', 'UNIFIED_AGENT.md'), 'utf8');