docs(guide): restructure into Installation / Instance admin / Domain admin
test / test (push) Has been cancelled

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>
This commit is contained in:
2026-08-14 15:45:38 +03:00
parent d9ab7bfa45
commit 403c76d17d
2 changed files with 304 additions and 220 deletions
+2 -2
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@@ -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
+297 -213
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@@ -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
- [Reverse proxy (mandatory)](#reverse-proxy-mandatory)
- [Local trial](#local-trial)
- [Environment variables](#environment-variables)
- [DNS setup](#dns-setup)
- [IP warmup](#ip-warmup)
- [Operations](#operations)
- [Rate limiting](#rate-limiting)
- [Backup, restore, and moving a single domain](#backup-restore-and-moving-a-single-domain)
- [Installation](#installation)
- [Reverse proxy (mandatory)](#reverse-proxy-mandatory)
- [Local trial](#local-trial)
- [Environment variables](#environment-variables)
- [First-time setup link](#first-time-setup-link)
- [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)
- [Published ports](#published-ports)
- [Fixed image tag](#fixed-image-tag)
- [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):**
- **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.
```sh
docker compose exec selfpost cat /data/setup-token
```
**Domain level (for *every* sending domain you add in the panel):**
- **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.
### Published ports
Skipping any of the three per-domain 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.
`deploy/docker-compose.yml` maps **465** and **587** to the host. Port 465
(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.
The panel checks both scopes for you and tells you what is actually published:
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.
### Fixed image tag
## 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
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
## Instance administration
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),
TLS 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
**Reload configuration** button re-applies OpenDKIM tables and the Postfix
sender map from the database — use it if daemons drifted from what the panel
shows after manual edits under `/data`.
- **Domains** (`/domains`) — add sending domains, inspect 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.
*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`.
### Status
`/status` shows supervised processes (Postfix, OpenDKIM, panel), TLS
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) — see
[Server-level DNS](#server-level-dns-ptrrdns); use *Re-check* after changing
DNS. The **Reload configuration** button re-applies OpenDKIM tables and the
Postfix sender map from the database — use it if daemons drifted from what
the panel shows after manual edits under `/data`.
### Mail queue and System log
- **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
[Backup, restore, and moving a single domain](#backup-restore-and-moving-a-single-domain).
- **Settings** (`/settings`) — change the administrator username and/or
password, and the panel-wide default DMARC report address (`rua=`) offered
when a domain doesn't set its own — see [DNS setup](#dns-setup). Application
SASL logins are separate and are not changed here.
- **Users** (`/users`, global administrator only) — create, edit, and delete
panel users. There are two roles:
- **Global administrator** — full access to every page and every domain,
### Settings
`/settings` changes the administrator username and/or password, and the
panel-wide default DMARC report address (`rua=`) offered when a domain
doesn't set its own — see
[Domain-level DNS](#domain-level-dns-spf-dkim-dmarc). Application SASL logins
are separate and are not changed here.
### 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
- **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.
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
in memory. Expiry is a sliding idle window (`PANEL_SESSION_IDLE_DAYS`, default
### Sessions
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
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
### Upgrading
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
`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.
### Container health
**First-time setup link.** 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:
The image declares a Docker `HEALTHCHECK` that probes `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](#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.
```sh
docker compose exec selfpost cat /data/setup-token
```
### Server-level DNS (PTR/rDNS)
## 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
level 2 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).
The [Status](#status) page verifies the server's hostname against this
record (forward-confirmed reverse DNS). Results are cached for a few
minutes; use *Re-check* right after publishing a record.
**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`
@@ -297,81 +310,54 @@ 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
window for **every** client IP sending as that domain. When unset, only
level 1 applies for non-privileged senders.
### Full backup and restore
**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.
**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 host:
When a level-2 ceiling is exceeded, Postfix returns a 4xx and the refusal is
recorded in Deliveries as `rejected`.
```sh
docker exec <container> selfpost-backup > selfpost-backup.tar.gz
```
**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.
**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
first successful start after restore, `manifest.json` from the archive is
**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 (see [Fixed image
tag](#fixed-image-tag)).
## Backup, restore, and moving a single domain
Restoring an archive taken **before** you invalidated a session (password
change, logout everywhere) can bring that session back: session rows travel
with the backup, and a browser that still holds the matching cookie is
logged in again once the idle timeout allows it. If a restore might do this,
changing every user's password afterwards clears it out.
Two related but distinct operations
([architecture.md](architecture.md) § Persistence):
**Alternative: archive `./data` while stopped.** If the service can be taken
offline, `docker compose down` then `tar czf selfpost-data.tar.gz ./data` on
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 the container is running: the database uses
WAL mode and a naive copy can capture an inconsistent snapshot. The
panel/CLI backup remains preferable when you cannot afford downtime because
it takes a consistent SQLite snapshot via the Backup API on a live
container.
- **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
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
first successful start after restore, `manifest.json` from the archive is
**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.
See also [Exporting and importing a single
domain](#exporting-and-importing-a-single-domain) — a different, domain-scoped
operation that also lives on the *Backup* page (`/backup`).
Restoring an archive taken **before** you invalidated a session (password
change, logout everywhere) can bring that session back: session rows travel
with the backup, and a browser that still holds the matching cookie is
logged in again once the idle timeout allows it. If a restore might do this,
changing every user's password afterwards clears it out.
Both a full backup and a domain export are **secrets** — they contain the
admin password hash (full backup) or working application credentials (domain
export) in the clear or in directly reversible form. Treat them like any
other credential material: restrict who can read them, don't email them
around — and encrypt them, which SelfPost can do for you.
**Alternative: archive `./data` while stopped.** If the service can be taken
offline, `docker compose down` then `tar czf selfpost-data.tar.gz ./data` on
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
the container is running: the database uses WAL mode and a naive copy can
capture an inconsistent snapshot. The panel/CLI backup remains preferable when
you cannot afford downtime because it takes a consistent SQLite snapshot via
the Backup API on a live container.
- **Export/import a single domain** (domain page → *Export domain* to write the
file, *Backup* → *Import a domain* to read it back in): 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, 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
backup) or working application credentials (domain export) in the clear or in
directly reversible form. Treat them like any other credential material:
restrict who can read them, don't email them 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
(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.
### Domains page
## 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`),
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 above:
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.
### Domain-level DNS (SPF, DKIM, DMARC)
For *every* sending domain you add in the panel:
- **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* (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).