docs(guide): restructure into Installation / Instance admin / Domain admin

Splits mixed DNS-setup, Operations, Rate-limiting, and Backup sections along the instance/domain boundary and fixes README anchors that pointed at the old #dns-setup heading. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-14 15:45:38 +03:00
parent d9ab7bfa45
commit 403c76d17d
2 changed files with 304 additions and 220 deletions
@@ -76,7 +76,7 @@ For every domain you add in the panel:
 - [ ] DKIM TXT record (value shown on the domain page)
 - [ ] DMARC `_dmarc` TXT record
-See [DNS setup](docs/guide.md#dns-setup) in the operator guide.
+See [Domain-level DNS](docs/guide.md#domain-level-dns-spf-dkim-dmarc) in the operator guide.
 ## Quick start
@@ -248,7 +248,7 @@ Before sending real mail:
 1. Confirm PTR/rDNS for the server IP points at `SELFPOST_HOSTNAME` (Status
   page → *Re-check*).
 2. For each domain you add in the panel, publish SPF, DKIM, and DMARC at the
-   same time ([DNS setup](docs/guide.md#dns-setup)).
+   same time ([Domain-level DNS](docs/guide.md#domain-level-dns-spf-dkim-dmarc)).
 3. Warm up a new IP gradually ([IP warmup](docs/guide.md#ip-warmup)).
 ### Ports and upgrades
@@ -3,21 +3,45 @@
 Detailed install, configuration, and day-to-day operations. For a short
 overview and quick start, see [README.md](../README.md).
 This guide has three parts: **[Installation](#installation)** (getting a
 container running with a working reverse proxy and TLS), **[Instance
 administration](#instance-administration)** (running and maintaining the
 SelfPost server itself — status, backups, users, upgrades), and **[Domain
 administration](#domain-administration)** (day-to-day work on the sending
 domains hosted on that instance — DNS, deliveries, rate limits, applications).
 ## Table of contents
 - [Installation](#installation)
  - [Reverse proxy (mandatory)](#reverse-proxy-mandatory)
  - [Local trial](#local-trial)
  - [Environment variables](#environment-variables)
- [DNS setup](#dns-setup)
+  - [First-time setup link](#first-time-setup-link)
 - [IP warmup](#ip-warmup)
 - [Operations](#operations)
 - [Rate limiting](#rate-limiting)
 - [Backup, restore, and moving a single domain](#backup-restore-and-moving-a-single-domain)
  - [Encrypting a backup or export](#encrypting-a-backup-or-export)
  - [Published ports](#published-ports)
  - [Fixed image tag](#fixed-image-tag)
 - [Instance administration](#instance-administration)
  - [Status](#status)
  - [Mail queue and System log](#mail-queue-and-system-log)
  - [Settings](#settings)
  - [Users](#users)
  - [Sessions](#sessions)
  - [Upgrading](#upgrading)
  - [Container health](#container-health)
  - [Server-level DNS (PTR/rDNS)](#server-level-dns-ptrrdns)
  - [Rate limiting — level 1 (IP backstop)](#rate-limiting--level-1-ip-backstop)
  - [Full backup and restore](#full-backup-and-restore)
    - [Encrypting a backup or export](#encrypting-a-backup-or-export)
 - [Domain administration](#domain-administration)
  - [Domains page](#domains-page)
  - [Domain-level DNS (SPF, DKIM, DMARC)](#domain-level-dns-spf-dkim-dmarc)
  - [IP warmup](#ip-warmup)
  - [Rate limiting — level 2 (domain and application)](#rate-limiting--level-2-domain-and-application)
  - [Deliveries](#deliveries)
  - [Exporting and importing a single domain](#exporting-and-importing-a-single-domain)
-## Reverse proxy (mandatory)
+## Installation
 ### Reverse proxy (mandatory)
 SelfPost's panel speaks plain HTTP and never terminates TLS itself — a reverse
 proxy in front of it is not optional. The proxy is also the project's only
@@ -51,7 +75,7 @@ and Traefik by default). A proxy that rewrites `Host` instead makes the panel
 reject every form submission as cross-origin — the log says so explicitly,
 printing the `Origin` and `Host` it compared.
-## Local trial
+### Local trial
 The [README quick start](../README.md#quick-start) runs a single container
 with `PANEL_COOKIE_SECURE=false` and port 8080 published on localhost. No
@@ -85,7 +109,7 @@ Add `-v /tmp/selfpost-certs:/etc/postfix/tls:ro` to the `docker run` command
 (and keep `SELFPOST_HOSTNAME=mail.local.test` so it matches the certificate CN).
 Clients must skip TLS verification — the cert is not from a public CA.
-## Environment variables
+### Environment variables
 Copy [deploy/.env.example](../deploy/.env.example) to `.env` next to your
 `docker-compose.yml`. The table below lists every variable an operator is
@@ -95,7 +119,7 @@ expected to set; defaults match the code exactly.
 |---|---|---|---|
 | `SELFPOST_HOSTNAME` | Mail-server identity: Postfix HELO/EHLO, SASL realm, certificate CN/SAN, and the hostname the PTR check expects. Bare FQDN only — no scheme or port. | *(required)* | `.env` |
 | `SUBMISSION_ENABLE` | When `true`, also listen on port 587 with STARTTLS (RFC 6409 submission) alongside the primary 465/smtps listener. | `false` | `.env` |
-| `RATE_LIMIT_MESSAGES_PER_IP` | Level-1 backstop: maximum messages one client IP may submit per window (Postfix `smtpd_client_message_rate_limit`). See [Rate limiting](#rate-limiting). | `100` | `.env` |
+| `RATE_LIMIT_MESSAGES_PER_IP` | Level-1 backstop: maximum messages one client IP may submit per window (Postfix `smtpd_client_message_rate_limit`). See [Rate limiting — level 1](#rate-limiting--level-1-ip-backstop). | `100` | `.env` |
 | `RATE_LIMIT_WINDOW_SECONDS` | Level-1 window length in seconds (Postfix `anvil_rate_time_unit`). | `3600` | `.env` |
 | `SEND_LOG_RETENTION_DAYS` | Days of send-log history kept before the background sweep deletes rows — the main driver of `/data` growth over time. | `90` | `.env` |
 | `PANEL_SESSION_IDLE_DAYS` | Sliding idle timeout for the panel login session, in days. There is no absolute cap: an admin who keeps coming back stays signed in indefinitely. | `7` | `.env` |
@@ -134,91 +158,64 @@ supported configuration:
  hours; logrotate keeps 14 rotated files on a daily schedule, and each
  rotation triggers `postfix reload`).
-## DNS setup
+### First-time setup link
-Two different scopes — don't confuse them:
+On first start the one-time setup URL is printed in the container log
 (`docker compose logs -f`) and written to `/data/setup-token` inside the
 container — `./data/setup-token` on the host, mode `0600` — then deleted when
 setup completes. The link is `https://<SELFPOST_HOSTNAME>/setup/<token>` (path
 token, not a query string), valid for ten minutes. If this host ships
 container logs to a central aggregator, prefer reading the file:
-**Server level (once, for the machine itself):**
+```sh
- **PTR/rDNS** for the server's IP, pointing at its mail hostname. Most
+docker compose exec selfpost cat /data/setup-token
-  receiving mail servers weigh this heavily; get it from whoever assigns the IP
+```
  (hosting provider's panel/support), not from your own DNS zone.
-**Domain level (for *every* sending domain you add in the panel):**
+### Published ports
 - **SPF** — a TXT record on the domain authorizing this server to send on its
  behalf (e.g. `v=spf1 a mx ip4:<server IP> -all`, adjusted to your setup).
 - **DKIM** — a TXT record with the exact value the panel shows on that
  domain's page (`domain page → DKIM TXT record`), one selector per domain.
 - **DMARC** — a `_dmarc` TXT record. The panel suggests `p=none` (monitoring
  only, safe to publish immediately). On a send-only relay the sending domain
  often has no inbox, so `rua=` is optional — configure a default report address
  in *Settings* or per domain when you have a mailbox that receives inbound mail
  elsewhere. If `rua=` points at another domain, publish `_report._dmarc` on that
  hub domain too; the panel checks it. Public mail hosts (Gmail, Outlook, …)
  cannot be used as external report destinations.
-Skipping any of the three per-domain records is the single most common reason
+`deploy/docker-compose.yml` maps **465** and **587** to the host. Port 465
-mail lands in spam even though SelfPost delivered it correctly — DKIM passing
+(smtps) is always active. Port **587** is published even when
-doesn't help if SPF/DMARC are absent. **Whenever you add a new domain in the
+`SUBMISSION_ENABLE=false`; nothing listens until you set it to `true` — harmless,
-panel, add its DNS records at the same time**, not later.
+but it can look like an open port in external scans.
-The panel checks both scopes for you and tells you what is actually published:
+### Fixed image tag
 the *Status* page verifies the server's hostname and its reverse record
 (forward-confirmed reverse DNS), and each domain's page shows a *DNS status*
 card comparing the published DKIM record against the key this server signs with,
 plus the domain's SPF, DMARC, and (when configured) DMARC report-authorisation
 records. Results are cached for a few minutes;
 use *Re-check* right after publishing a record. The SPF check is deliberately
 shallow — it looks for a mechanism that literally covers this server's address
 and does not follow `include:` or `redirect=`, so a record that authorizes the
 server through an include is reported as "cannot tell" rather than as a failure.
-## IP warmup
+`deploy/docker-compose.yml` pins an explicit version (`ghcr.io/mixeme/selfpost:X.Y.Z`),
 deliberately never `:latest`. The current pin is `1.2.5`. Intermediate
 CHANGELOG sections (`0.2.0`…`0.6.0`) record development cuts from before that
 image was published. Pinning matters because of the backup version check (see
 [Full backup and restore](#full-backup-and-restore)): the panel binary's
 embedded version and the image tag that produced it are the same value by
 construction (the release CI stamps both from one git tag — see
 `.github/workflows/release.yml`), so the pin is what makes "restore into the
 same version" a checkable fact rather than a guess. Upgrade by bumping the tag
 deliberately, not by riding a moving target — see [Upgrading](#upgrading).
-A brand-new IP has no sending history, so receiving servers are cautious with
+## Instance administration
 it regardless of how correct your DKIM/SPF/DMARC are. Start with low volume to
 a domain, increase gradually over days/weeks rather than sending everything on
 day one, and check the IP against major blocklists (Spamhaus and similar)
 before and during warmup. This is inherent to how mail reputation works on the
 public internet, not something SelfPost's configuration can shortcut.
 ## Operations
 After sign-in the panel opens on **Status** — the place to answer "is the
 service healthy and will mail be accepted?"
- **Status** (`/status`) — supervised processes (Postfix, OpenDKIM, panel),
+### Status
-  TLS certificate validity and expiry, milter socket presence, and a short
+
-  Postfix queue summary. The **Machine** card adds the resource usage of the
+`/status` shows supervised processes (Postfix, OpenDKIM, panel), TLS
-  host underneath — processor (core and thread counts), memory and swap, and
+certificate validity and expiry, milter socket presence, and a short Postfix
 queue summary. The **Machine** card adds the resource usage of the host
 underneath — processor (core and thread counts), memory and swap, and
 per-interface network throughput and totals — read from the kernel's
 counters; CPU and throughput are measured between refreshes, so they appear
 one refresh after the page opens. A fully busy processor or a machine out of
 memory is a warning here, because both delay or kill the mail path;
 throughput is only reported. The hostname block compares `SELFPOST_HOSTNAME`
 against the PTR record the internet publishes for this server's IP
-  (forward-confirmed reverse DNS); use *Re-check* after changing DNS. The
+(forward-confirmed reverse DNS) — see
-  **Reload configuration** button re-applies OpenDKIM tables and the Postfix
+[Server-level DNS](#server-level-dns-ptrrdns); use *Re-check* after changing
-  sender map from the database — use it if daemons drifted from what the panel
+DNS. The **Reload configuration** button re-applies OpenDKIM tables and the
-  shows after manual edits under `/data`.
+Postfix sender map from the database — use it if daemons drifted from what
- **Domains** (`/domains`) — add sending domains, inspect each domain's DKIM
+the panel shows after manual edits under `/data`.
-  TXT value, SPF/DMARC checks, and SASL applications. Per-domain rate limits
+
-  (level 2) and trusted-IP application overrides are configured here.
+### Mail queue and System log
-  *Export domain* writes a single-domain archive;
+
  *Import a domain* on the Backup page reads one back in.
 - **Deliveries** (`/deliveries`) — searchable send log with server-side filters
  by domain and application. A row identifies its message and nothing more —
  time, sender, recipient, subject and status `queued` (accepted, not yet
  delivered), `sent` (handed off successfully), `deferred` (Postfix is retrying),
  `bounced` (final failure), or `rejected` (refused — for example by a level-2
  rate limit); *Details* opens that row's own page
  (`/deliveries/{id}`). That page carries the sending domain, the application it
  was submitted under, the Postfix queue id and the journal id, beside the
  message's history — when it was accepted and what Postfix later reported for
  the recipient — and, under both, the `mail.log` lines for its queue id: the
  connection to the receiving server, the server's reply, and the status that
  reply was filed as. Rows outlive `mail.log`, so an older message's lines may
  have rotated away; the page says so. Retention is controlled by
  `SEND_LOG_RETENTION_DAYS`.
 - **Mail queue** (`/mail-queue`) — live view of messages Postfix is still
  trying to deliver or deferring.
 - **System log** (`/system-log`) — tail of `/data/log/mail.log` (Postfix and
@@ -227,28 +224,36 @@ service healthy and will mail be accepted?"
  hours. It lives in the data volume, so it survives a container recreate along
  with the rest of the state — `./data/log/` on the host — but it is *not*
  included in backups: it is diagnostics, not state.
- **Backup** (`/backup`) — download a full-server backup; the same page hosts
+
-  the domain-import form (`POST /domains/import`). See
+### Settings
-  [Backup, restore, and moving a single domain](#backup-restore-and-moving-a-single-domain).
+
- **Settings** (`/settings`) — change the administrator username and/or
+`/settings` changes the administrator username and/or password, and the
-  password, and the panel-wide default DMARC report address (`rua=`) offered
+panel-wide default DMARC report address (`rua=`) offered when a domain
-  when a domain doesn't set its own — see [DNS setup](#dns-setup). Application
+doesn't set its own — see
-  SASL logins are separate and are not changed here.
+[Domain-level DNS](#domain-level-dns-spf-dkim-dmarc). Application SASL logins
- **Users** (`/users`, global administrator only) — create, edit, and delete
+are separate and are not changed here.
-  panel users. There are two roles:
+
 ### Users
 `/users` (global administrator only) creates, edits, and deletes panel users.
 There are two roles:
 - **Global administrator** — full access to every page and every domain,
  including Users, Backup, Status, Mail queue, and System log.
 - **Domain-admin** — scoped to one or more domains assigned by a global
  administrator. Sees only those domains' pages, applications, and
  Deliveries rows; `/users`, `/backup`, `/status`, `/mail-queue`, and
  `/system-log` are not reachable (404). A domain-admin can *export* the
-    domains assigned to them — see the note on working credentials below.
+  domains assigned to them — see
  [Exporting and importing a single domain](#exporting-and-importing-a-single-domain).
 The panel refuses to remove or demote the **last** global administrator, so
 it can never end up with none.
-**Sessions.** A login survives a container restart: sessions live in SQLite, not
+### Sessions
-in memory. Expiry is a sliding idle window (`PANEL_SESSION_IDLE_DAYS`, default
+
 A login survives a container restart: sessions live in SQLite, not in
 memory. Expiry is a sliding idle window (`PANEL_SESSION_IDLE_DAYS`, default
 seven days) with no absolute lifetime cap — an admin who keeps using the panel
 stays signed in indefinitely. HTMX polling on the monitoring screens
 (Deliveries, Mail queue, System log, and the Status health fragment) does
@@ -256,40 +261,48 @@ stays signed in indefinitely. HTMX polling on the monitoring screens
 session alive forever. Changing the password signs out every other session but
 leaves the current browser signed in.
-**Upgrading.** Bump the pinned image tag in `docker-compose.yml` to the target
+### Upgrading
-release, then `docker compose up -d`. The backup version check requires the
+
-running image to match the version that created a full backup — see [Fixed image
+Bump the pinned image tag in `docker-compose.yml` to the target release, then
 `docker compose up -d`. The backup version check requires the running image
 to match the version that created a full backup — see [Fixed image
 tag](#fixed-image-tag).
-**Container health.** The image declares a Docker `HEALTHCHECK` that probes
+### Container health
 `GET /healthz` on port 8080 (unauthenticated). It returns `200 ok` when
 OpenDKIM, the panel, and Postfix are all `RUNNING` under supervisord;
 otherwise `503 unhealthy`. This catches a dead mail path that would still leave
 the HTTP server up, but it does **not** verify TLS certificates, DNS records,
 or end-to-end delivery — use the authenticated **Status** page for that. External
 monitoring can use the same endpoint through the reverse proxy if you expose it,
 or poll `docker inspect` health state on the host.
-**First-time setup link.** On first start the one-time setup URL is printed in
+The image declares a Docker `HEALTHCHECK` that probes `GET /healthz` on port
-the container log (`docker compose logs -f`) and written to `/data/setup-token`
+8080 (unauthenticated). It returns `200 ok` when OpenDKIM, the panel, and
-inside the container — `./data/setup-token` on the host, mode `0600` — then
+Postfix are all `RUNNING` under supervisord; otherwise `503 unhealthy`. This
-deleted when setup completes. The link is
+catches a dead mail path that would still leave the HTTP server up, but it
-`https://<SELFPOST_HOSTNAME>/setup/<token>` (path token, not a query string),
+does **not** verify TLS certificates, DNS records, or end-to-end delivery —
-valid for ten minutes. If this host ships container logs to a central
+use the authenticated [Status](#status) page for that. External monitoring
-aggregator, prefer reading the file:
+can use the same endpoint through the reverse proxy if you expose it, or poll
 `docker inspect` health state on the host.
-```sh
+### Server-level DNS (PTR/rDNS)
 docker compose exec selfpost cat /data/setup-token
 ```
-## Rate limiting
+Once, for the machine itself: **PTR/rDNS** for the server's IP, pointing at
 its mail hostname. Most receiving mail servers weigh this heavily; get it
 from whoever assigns the IP (hosting provider's panel/support), not from
 your own DNS zone.
-SelfPost applies two independent layers; both can refuse a submission, but only
+The [Status](#status) page verifies the server's hostname against this
-level 2 writes a `rejected` row in the send log. Level-2 ceilings set in the
+record (forward-confirmed reverse DNS). Results are cached for a few
-panel cannot exceed level 1 (the panel shows the level-1 values and rejects
+minutes; use *Re-check* right after publishing a record.
 higher numbers).
-**Level 1 (IP backstop)** — always on, configured via `.env`:
+Per-domain DNS (SPF, DKIM, DMARC) is a separate scope — see
 [Domain-level DNS](#domain-level-dns-spf-dkim-dmarc).
 ### Rate limiting — level 1 (IP backstop)
 SelfPost applies two independent layers of rate limiting; both can refuse a
 submission, but only level 2 (domain/application, see
 [Domain administration](#rate-limiting--level-2-domain-and-application))
 writes a `rejected` row in the send log. Level-2 ceilings set in the panel
 cannot exceed level 1 (the panel shows the level-1 values and rejects higher
 numbers).
 Level 1 is always on, configured via `.env`:
 - `RATE_LIMIT_MESSAGES_PER_IP` → Postfix `smtpd_client_message_rate_limit`
 - `RATE_LIMIT_WINDOW_SECONDS` → Postfix `anvil_rate_time_unit`
@@ -297,37 +310,16 @@ higher numbers).
 This is an anvil limit per connecting client IP. It keeps working even if the
 journal-milter (level 2) is down. There is no per-IP bypass.
-**Level 2 — domain** — optional, on each domain's page. A message ceiling and
+### Full backup and restore
 window for **every** client IP sending as that domain. When unset, only
 level 1 applies for non-privileged senders.
-**Level 2 — application (trusted IPs)** — optional override on an application:
+**Full backup** (whole `/data` except `log/`: SQLite, all domains' DKIM keys,
 list one or more client IPs and a ceiling **strictly above** the domain limit
 (still ≤ level 1). Connections from those IPs use the application ceiling and
 skip the domain check. Other IPs stay under the domain limit (or level 1 alone).
 An application override without trusted IPs is inactive.
 When a level-2 ceiling is exceeded, Postfix returns a 4xx and the refusal is
 recorded in Deliveries as `rejected`.
 **Level 2 is best-effort, not a guarantee.** It runs inside the journal-milter
 and is deliberately fail-open: if the rate-limit lookup hits a store error, or
 the connecting client's IP is not available to the milter, level 2 is skipped
 and the message is accepted rather than held up. Level 1 (the Postfix anvil
 limit above) is the backstop that keeps working even when level 2 cannot run.
 ## Backup, restore, and moving a single domain
 Two related but distinct operations
 ([architecture.md](architecture.md) § Persistence):
 - **Full backup** (whole `/data` except `log/`: SQLite, all domains' DKIM keys,
 all applications' SASL credentials, `manifest.json` with the version that
-  created it): panel button (*Backup* → *Full backup*), or from the
+created it): panel button (*Backup* → *Full backup*), or from the host:
-  host:
+
 ```sh
 docker exec <container> selfpost-backup > selfpost-backup.tar.gz
 ```
 **Restore** means unpacking that archive into a fresh `/data` bind mount and
 starting a container of the **exact same image version** that created it —
 SelfPost refuses to start otherwise and tells you which tag to use. On the
@@ -335,7 +327,8 @@ Two related but distinct operations
 **deleted** — it guards only that one boot, so a later in-place upgrade is
 not blocked. This is why the compose file pins a fixed tag rather than
 `:latest`: without a known version, there'd be no way to tell which image
-  restoring a given backup actually requires.
+restoring a given backup actually requires (see [Fixed image
 tag](#fixed-image-tag)).
 Restoring an archive taken **before** you invalidated a session (password
 change, logout everywhere) can bring that session back: session rows travel
@@ -348,30 +341,23 @@ Two related but distinct operations
 the host is safe — nothing is writing to SQLite. Unlike the panel/CLI backup
 this sweeps in `./data/log/` too, which is Postfix's raw log and usually the
 bulk of the archive; add `--exclude=./data/log` if you only want the state.
-  Do **not** tar `./data` while
+Do **not** tar `./data` while the container is running: the database uses
-  the container is running: the database uses WAL mode and a naive copy can
+WAL mode and a naive copy can capture an inconsistent snapshot. The
-  capture an inconsistent snapshot. The panel/CLI backup remains preferable when
+panel/CLI backup remains preferable when you cannot afford downtime because
-  you cannot afford downtime because it takes a consistent SQLite snapshot via
+it takes a consistent SQLite snapshot via the Backup API on a live
-  the Backup API on a live container.
+container.
- **Export/import a single domain** (domain page → *Export domain* to write the
+See also [Exporting and importing a single
-  file, *Backup* → *Import a domain* to read it back in): moves one domain — its DKIM key and its applications' **working**
+domain](#exporting-and-importing-a-single-domain) — a different, domain-scoped
-  SASL passwords — to a different SelfPost instance without regenerating
+operation that also lives on the *Backup* page (`/backup`).
  anything, so DNS (the DKIM TXT record) doesn't need to change. Unlike a full
  restore, this works across different hostnames/instances. *Import* is
  global-administrator only; *export* is available to any user who can access
  the domain, **including a domain-admin** for a domain assigned to them — so
  a domain-admin can walk away with that domain's working SASL passwords in
  the clear. Weigh that when deciding which domains to assign to a
  domain-admin account.
-Both files are **secrets** — they contain the admin password hash (full
+Both a full backup and a domain export are **secrets** — they contain the
-backup) or working application credentials (domain export) in the clear or in
+admin password hash (full backup) or working application credentials (domain
-directly reversible form. Treat them like any other credential material:
+export) in the clear or in directly reversible form. Treat them like any
-restrict who can read them, don't email them around — and encrypt them, which
+other credential material: restrict who can read them, don't email them
-SelfPost can do for you.
+around — and encrypt them, which SelfPost can do for you.
-### Encrypting a backup or export
+#### Encrypting a backup or export
 Both download forms carry an **Encrypt with a password** checkbox. Ticked, the
 file that comes down is an encrypted envelope instead of the plain archive:
@@ -411,21 +397,119 @@ docker exec -e SELFPOST_BACKUP_PASSWORD="$PW" <container> selfpost-backup > back
 With no password set, the CLI keeps writing the plain `.tar.gz` it always has.
-## Published ports
+## Domain administration
-`deploy/docker-compose.yml` maps **465** and **587** to the host. Port 465
+### Domains page
 (smtps) is always active. Port **587** is published even when
 `SUBMISSION_ENABLE=false`; nothing listens until you set it to `true` — harmless,
 but it can look like an open port in external scans.
-## Fixed image tag
+`/domains` adds sending domains, and shows each domain's DKIM TXT value,
 SPF/DMARC checks, and SASL applications. Per-domain rate limits (level 2) and
 trusted-IP application overrides are configured here — see [Rate limiting —
 level 2](#rate-limiting--level-2-domain-and-application). *Export domain*
 writes a single-domain archive; *Import a domain* on the Backup page reads
 one back in — see [Exporting and importing a single
 domain](#exporting-and-importing-a-single-domain).
-`deploy/docker-compose.yml` pins an explicit version (`ghcr.io/mixeme/selfpost:X.Y.Z`),
+### Domain-level DNS (SPF, DKIM, DMARC)
-deliberately never `:latest`. The current pin is `1.2.5`. Intermediate
+
-CHANGELOG sections (`0.2.0`…`0.6.0`) record development cuts from before that
+For *every* sending domain you add in the panel:
-image was published. Pinning matters because of the backup version check above:
+
-the panel binary's embedded version and the image tag that produced it are the
+- **SPF** — a TXT record on the domain authorizing this server to send on its
-same value by construction (the release CI stamps both from one git tag — see
+  behalf (e.g. `v=spf1 a mx ip4:<server IP> -all`, adjusted to your setup).
-`.github/workflows/release.yml`), so the pin is what makes "restore into the
+- **DKIM** — a TXT record with the exact value the panel shows on that
-same version" a checkable fact rather than a guess. Upgrade by bumping the tag
+  domain's page (`domain page → DKIM TXT record`), one selector per domain.
-deliberately, not by riding a moving target.
+- **DMARC** — a `_dmarc` TXT record. The panel suggests `p=none` (monitoring
  only, safe to publish immediately). On a send-only relay the sending domain
  often has no inbox, so `rua=` is optional — configure a default report address
  in *Settings* (see [Settings](#settings)) or per domain when you have a
  mailbox that receives inbound mail elsewhere. If `rua=` points at another
  domain, publish `_report._dmarc` on that hub domain too; the panel checks
  it. Public mail hosts (Gmail, Outlook, …) cannot be used as external
  report destinations.
 Skipping any of the three records is the single most common reason mail
 lands in spam even though SelfPost delivered it correctly — DKIM passing
 doesn't help if SPF/DMARC are absent. **Whenever you add a new domain in the
 panel, add its DNS records at the same time**, not later.
 Each domain's page shows a *DNS status* card comparing the published DKIM
 record against the key this server signs with, plus the domain's SPF,
 DMARC, and (when configured) DMARC report-authorisation records. Results are
 cached for a few minutes; use *Re-check* right after publishing a record.
 The SPF check is deliberately shallow — it looks for a mechanism that
 literally covers this server's address and does not follow `include:` or
 `redirect=`, so a record that authorizes the server through an include is
 reported as "cannot tell" rather than as a failure.
 Server-level DNS (the PTR/rDNS record) is a separate, once-per-machine scope
 — see [Server-level DNS](#server-level-dns-ptrrdns).
 ### IP warmup
 A brand-new IP has no sending history, so receiving servers are cautious with
 it regardless of how correct your DKIM/SPF/DMARC are. Start with low volume to
 a domain, increase gradually over days/weeks rather than sending everything on
 day one, and check the IP against major blocklists (Spamhaus and similar)
 before and during warmup. This is inherent to how mail reputation works on the
 public internet, not something SelfPost's configuration can shortcut.
 ### Rate limiting — level 2 (domain and application)
 Level 2 is optional, configured on each domain's page, and layers on top of
 the always-on [level-1 IP backstop](#rate-limiting--level-1-ip-backstop).
 Level-2 ceilings cannot exceed level 1 (the panel shows the level-1 values
 and rejects higher numbers). When a level-2 ceiling is exceeded, Postfix
 returns a 4xx and the refusal is recorded in [Deliveries](#deliveries) as
 `rejected`.
 **Level 2 — domain** — a message ceiling and window for **every** client IP
 sending as that domain. When unset, only level 1 applies for non-privileged
 senders.
 **Level 2 — application (trusted IPs)** — optional override on an
 application: list one or more client IPs and a ceiling **strictly above**
 the domain limit (still ≤ level 1). Connections from those IPs use the
 application ceiling and skip the domain check. Other IPs stay under the
 domain limit (or level 1 alone). An application override without trusted
 IPs is inactive.
 **Level 2 is best-effort, not a guarantee.** It runs inside the
 journal-milter and is deliberately fail-open: if the rate-limit lookup hits
 a store error, or the connecting client's IP is not available to the
 milter, level 2 is skipped and the message is accepted rather than held up.
 Level 1 is the backstop that keeps working even when level 2 cannot run.
 ### Deliveries
 `/deliveries` is a searchable send log with server-side filters by domain
 and application. A row identifies its message and nothing more — time,
 sender, recipient, subject and status `queued` (accepted, not yet
 delivered), `sent` (handed off successfully), `deferred` (Postfix is
 retrying), `bounced` (final failure), or `rejected` (refused — for example
 by a [level-2 rate limit](#rate-limiting--level-2-domain-and-application));
 *Details* opens that row's own page (`/deliveries/{id}`). That page carries
 the sending domain, the application it was submitted under, the Postfix
 queue id and the journal id, beside the message's history — when it was
 accepted and what Postfix later reported for the recipient — and, under
 both, the `mail.log` lines for its queue id: the connection to the
 receiving server, the server's reply, and the status that reply was filed
 as. Rows outlive `mail.log`, so an older message's lines may have rotated
 away; the page says so. Retention is controlled by
 `SEND_LOG_RETENTION_DAYS`.
 ### Exporting and importing a single domain
 Domain page → *Export domain* to write the file, *Backup* → *Import a
 domain* to read it back in. This moves one domain — its DKIM key and its
 applications' **working** SASL passwords — to a different SelfPost instance
 without regenerating anything, so DNS (the DKIM TXT record) doesn't need to
 change. Unlike a full restore (see [Full backup and
 restore](#full-backup-and-restore)), this works across different
 hostnames/instances. *Import* is global-administrator only; *export* is
 available to any user who can access the domain, **including a domain-admin**
 for a domain assigned to them — so a domain-admin can walk away with that
 domain's working SASL passwords in the clear. Weigh that when deciding which
 domains to assign to a domain-admin account.
 A domain export is a secret in the same way a full backup is, and can be
 encrypted the same way — see [Encrypting a backup or
 export](#encrypting-a-backup-or-export).