Files
computer-playbook/roles/web-app-stalwart/README.md
kevinveenbirkenbachandClaude Opus 5.5 193e7d4463 fix(web-app-mailu): set the role's lifecycle to eol
Mailu is superseded by web-app-stalwart and the project no longer
maintains it. Its OIDC flavor runs the archived heviat/Mailu-OIDC images
(the webmail ships Roundcube 1.6.9 and PHP 8.3.15), and its unbound
sidecar fails DNS since the root KSK rollover (#1303). Rather than fix
a role on its way out, mark it end of life:

- meta/services.yml: lifecycle deprecated -> eol. The updater and the
  image mirror now skip the role (the mirrored image set drops from
  189 to 188 entries), and default CI keeps excluding it as before.
- README.md: the banner now states that the project neither maintains
  nor tests the role, that operators use it at their own risk, and
  links upstream Mailu for support, as lifecycle.md requires for eol.
  The migration pointer to web-app-stalwart stays.
- web-app-stalwart README: "deprecated" becomes "end-of-life".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-30 20:10:49 +01:00

399 lines
24 KiB
Markdown

# Stalwart Mail Server
## Description
Runs [Stalwart](https://stalw.art/) — a secure, all-in-one mail and
collaboration server — as the platform's email provider. A single hardened
service speaks **SMTP, Submission, IMAP, POP3, JMAP, ManageSieve, CalDAV,
CardDAV and WebDAV**, with a **built-in spam filter**, **DKIM/DMARC** signing
and a **WebAdmin + REST management API**.
This role replaces the end-of-life [`web-app-mailu`](../web-app-mailu/) role.
Applications send mail through the same provider-agnostic abstraction
(`lookup('email')` / [`sys-svc-mail`](../sys-svc-mail/)) — no consumer changes
are needed beyond the provider repoint.
## Overview
Compared with Mailu's multi-container stack, Stalwart collapses the mail server
into one binary. This role runs:
| Container | Purpose |
|-----------|---------|
| `stalwart` | SMTP/IMAP/JMAP/POP3/Sieve/DAV + built-in spam filter + WebAdmin/REST API |
| `webmail` (Roundcube) | Browser webmail (parity with Mailu) |
| `clamav` | Attachment antivirus, called as an SMTP DATA-stage milter |
| `postgres` *(shared)* | Account / mail / metadata store |
Dynamic state (domains, accounts, passwords, DKIM, certificates) is administered
at runtime via the JMAP management API; `config.json` only bootstraps the data
store. Spam filtering is built into Stalwart; **antivirus** is provided by the
`clamav` container (registered via `x:MtaMilter`, `services.clamav.enabled` —
set it to `false` to run spam-only). Infected mail is rejected at DATA.
```mermaid
flowchart LR
subgraph edge["Front proxy (TLS)"]
MAIL_VHOST["mail.<domain> (WebAdmin)"]
WEBMAIL_VHOST["webmail.<domain> (Roundcube)"]
end
subgraph stack["web-app-stalwart compose stack"]
STALWART["stalwart<br/>SMTP/IMAP/JMAP/POP3/Sieve/DAV<br/>+ WebAdmin + REST API"]
WEBMAIL["webmail (Roundcube)"]
CLAMAV["clamav (DATA-stage milter)"]
PG[("postgres<br/>(shared platform DB)")]
end
KC["Keycloak<br/>OIDC directory + SSO"]
APPS["Platform apps<br/>(no-reply bot via msmtp)"]
WORLD(("Internet<br/>ports 25/465/587/143/993/..."))
MAIL_VHOST --> STALWART
WEBMAIL_VHOST --> WEBMAIL
WEBMAIL -- "IMAP 993 / SMTP 465<br/>XOAUTH2 (stalwart-webmail client)" --> STALWART
STALWART -- "milter" --> CLAMAV
STALWART --- PG
STALWART -- "OIDC directory<br/>(token validation)" --> KC
MAIL_VHOST -. "SPA login: PKCE<br/>(stalwart-webui client)" .-> KC
WEBMAIL_VHOST -. "OAuth login" .-> KC
APPS -- "SMTPS :465, AUTH<br/>(bot credential from the token store)" --> STALWART
WORLD <-- "public mail ports<br/>(only when active MAIL_PROVIDER)" --> STALWART
```
## Cosmos
The diagram places Stalwart Mail Server in the Infinito.Nexus cosmos: the components it deploys (capabilities), the central services it consumes (dependencies), and its outward reach (federation and bridged external networks).
```mermaid
flowchart LR
subgraph deps [Dependencies]
dep_svc_bkp_volume_2_local["svc-bkp-volume-2-local 💻"]
dep_svc_db_postgres["svc-db-postgres 🐳🐝"]
dep_svc_net_tor["svc-net-tor 🐳🐝"]
dep_svc_net_tor_smtp["svc-net-tor-smtp 🐳🐝"]
dep_web_app_dashboard["web-app-dashboard 🐳🐝"]
dep_web_app_keycloak["web-app-keycloak 🐳🐝"]
dep_web_app_matomo["web-app-matomo 🐳🐝"]
dep_web_app_prometheus["web-app-prometheus 🐳🐝"]
dep_web_svc_css["web-svc-css 💻"]
dep_web_svc_logout["web-svc-logout 🐳🐝"]
end
subgraph role [web-app-stalwart 🐳🐝]
svc_sso["sso"]
svc_logout["logout"]
svc_dashboard["dashboard"]
svc_matomo["matomo"]
svc_container_backup["container_backup"]
svc_stalwart["stalwart"]
svc_postgres["postgres"]
svc_webmail["webmail"]
svc_clamav["clamav"]
svc_css["css"]
svc_prometheus["prometheus"]
svc_tor["tor"]
svc_tor_smtp["tor-smtp"]
end
subgraph dependents [Dependents]
dpt_sys_ctl_alm_email["sys-ctl-alm-email 💻"]
dpt_web_app_akaunting["web-app-akaunting 🐳🐝"]
dpt_web_app_baserow["web-app-baserow 🐳🐝"]
dpt_web_app_bigbluebutton["web-app-bigbluebutton 🐳🐝"]
dpt_web_app_bluesky["web-app-bluesky 🐳🐝"]
dpt_web_app_bookwyrm["web-app-bookwyrm 🐳🐝"]
dpt_web_app_bridgy_fed["web-app-bridgy-fed 🐳🐝"]
dpt_web_app_checkmk["web-app-checkmk 🐳🐝"]
dpt_web_app_confluence["web-app-confluence 🐳🐝"]
dpt_web_app_decidim["web-app-decidim 🐳🐝"]
dpt_web_app_discourse["web-app-discourse 🐳🐝"]
dpt_web_app_erpnext["web-app-erpnext 🐳🐝"]
dpt_more["..."]
end
dep_svc_bkp_volume_2_local -. "0..1" .-> svc_container_backup
dep_svc_db_postgres -. "0..1" .-> svc_postgres
dep_svc_net_tor -. "0..1" .-> svc_tor
dep_svc_net_tor -. "0..1" .-> svc_tor_smtp
dep_svc_net_tor_smtp -. "0..1" .-> svc_tor_smtp
dep_web_app_dashboard -. "0..1" .-> svc_dashboard
dep_web_app_keycloak -. "0..1" .-> svc_sso
dep_web_app_matomo -. "0..1" .-> svc_matomo
dep_web_app_prometheus -. "0..1" .-> svc_prometheus
dep_web_svc_css -. "0..1" .-> svc_css
dep_web_svc_logout -. "0..1" .-> svc_logout
svc_stalwart -- "1:1" --> dpt_more
svc_stalwart -- "1:1" --> dpt_sys_ctl_alm_email
svc_stalwart -. "0..1" .-> dpt_web_app_akaunting
svc_stalwart -. "0..1" .-> dpt_web_app_baserow
svc_stalwart -. "0..1" .-> dpt_web_app_bigbluebutton
svc_stalwart -. "0..1" .-> dpt_web_app_bluesky
svc_stalwart -. "0..1" .-> dpt_web_app_bookwyrm
svc_stalwart -- "0..0" --> dpt_web_app_bridgy_fed
svc_stalwart -. "0..1" .-> dpt_web_app_checkmk
svc_stalwart -- "0..0" --> dpt_web_app_confluence
svc_stalwart -. "0..1" .-> dpt_web_app_decidim
svc_stalwart -. "0..1" .-> dpt_web_app_discourse
svc_stalwart -. "0..1" .-> dpt_web_app_erpnext
linkStyle 18,20 stroke:red;
```
Solid `1:1` edges are fixed relationships; dashed `0..1` edges are conditional (enabled only in matching deployments); red `0..0` edges are turned off in this role. Node markers show the role's deploy modes (💻 host, 🐳 compose, 🐝 swarm); ❌ marks a service that is explicitly turned off, and ⚙️ an Ansible role dependency declared in `meta/main.yml`.
## SSO (Keycloak / OpenID Connect)
When `web-app-keycloak` is present the role joins the shared Keycloak client and
delegates **interactive** authentication to Keycloak:
- **WebAdmin + IMAP/SMTP/JMAP** authenticate against an **OIDC directory**
(`tasks/06_oidc.yml`): Stalwart validates Keycloak-issued tokens, matching the
`preferred_username` claim to the provisioned account.
- **Roundcube** logs users in over OAuth2 and talks to Stalwart with **XOAUTH2**
(`templates/roundcube-oauth.inc.php.j2`).
- The OIDC directory skips the audience check and gives Keycloak tokens without
Stalwart scopes access to mail, contacts, calendars and files
(`STALWART_OIDC_TOKEN_VALIDATION`). Tokens of the `stalwart-webui` client get
full access, because the WebUI Application names it as its `oauthClientId`.
**Design constraint (validated against the live JMAP schema):** Stalwart's
authentication directory is *Internal XOR one external directory* — there is no
chaining or fallback. Enabling SSO therefore **disables the account password**
for every account, including the machine `no-reply` account. App passwords are
checked before the directory and keep working, so with SSO enabled the role:
1. Creates one app password per bot account, acting for that account as the
recovery admin (`tasks/04_manage_user/app_password.yml`), and
2. Stores it in the token store, where
[`plugins/lookup/email.py`](../../plugins/lookup/email.py) reads the SMTP
password of the `no-reply` client.
A bot gets a new app password when its entry named
`STALWART_BOT_APP_PASSWORD_DESCRIPTION` is deleted in Stalwart or its token is
removed from the token store. The app password it replaces is renamed to
`STALWART_BOT_APP_PASSWORD_RETIRED_DESCRIPTION` and stays valid until the
service-loader post-load flush drops it
(`tasks/04_manage_user/app_password_drop.yml`), or until right after the new
one is stored when the role runs outside the service loader. A deploy that
stops before the flush leaves it to the next deploy. Relaying stays limited to
authenticated sessions in both modes (`STALWART_RELAY_RULE`).
With SSO disabled the role uses the Internal directory and the bot's derived
account password.
## WebUI sign-in
The WebUI Application always names `stalwart-webui` (`STALWART_WEBUI_OAUTH_CLIENT_ID`) as its `oauthClientId`, with and without SSO.
Where the WebUI sends a login depends on the account:
| Account | Authorization server | Client `stalwart-webui` |
|---|---|---|
| Account in a domain bound to the Keycloak OIDC directory | Keycloak | Keycloak client from `templates/keycloak/clients.json.j2` |
| Recovery admin (`STALWART_ADMIN_USER`), and every account while SSO is off | Stalwart | OAuth client the role registers in Stalwart (`tasks/02_webadmin.yml`) |
The role registers that Stalwart client over JMAP (`templates/jmap/oauth_client/`) as a public first-party client, with one redirect URI `<origin>/<prefix>/oauth/callback` and one post-logout URI `<origin>/<prefix>/login` per URL prefix of the WebUI Application.
`<origin>` is the role's canonical WebUI URL (`STALWART_WEBUI_BASE_URL`), so a Tor deployment registers its `http://` onion origin.
Every deploy compares the registered client with that target and updates it when they differ.
A deployment that serves the WebUI on a further origin MUST add that origin's URIs to [`templates/jmap/oauth_client/webui.json.j2`](templates/jmap/oauth_client/webui.json.j2), because a URI added in Stalwart alone is removed by the next deploy.
Stalwart's login page asks for consent before the password form for every registered client, so a native WebUI login shows an **Allow** step.
## Calendar & Contacts (CalDAV / CardDAV / WebDAV)
Stalwart serves DAV natively on the mail HTTP listener — no extra container
(Mailu used a separate Radicale service). Clients auto-discover via
`https://mail.<domain>/.well-known/{caldav,carddav}`, which redirect to
`https://mail.<domain>/dav/cal` and `/dav/card`. Authenticate with the mailbox
account (or the Keycloak SSO token when SSO is enabled).
## Design Decisions
- **Client ports are implicit-TLS only (465/993/995).** Stalwart's default
configuration binds no STARTTLS listeners, so the role neither publishes
587/143/110 nor advertises them via SRV records.
- **The WebUI (WebAdmin) bundle is staged by the controller.** Stalwart fetches
it from GitHub on first boot, which fails behind restricted egress; the
controller downloads it into a host-level cache (matrix rounds purge the
instance dir, and per-round downloads hit GitHub rate limits) and bind-mounts
it read-only. The `update:` block next to `webui_version` in
`meta/services.yml` names the upstream tags, so the version-source updater
bumps the bundle on its own, within the `v2.` line that server 1.x serves.
- **The embedded PostgreSQL pins the plain `postgres` image** — the platform's
postgis default defeats baudolo's substring database detection and would
degrade backups to torn live-file snapshots. `backup.project_hard_restart`
brings the whole project back through one coherent restart after baudolo's
per-volume stop/start cycles.
- **ClamAV runs fail-open with short milter timeouts** so mail keeps flowing
while clamd warms its signature database instead of blocking the DATA stage.
- **DMARC aggregate reports go to the mailbox of
`services.stalwart.dmarc.rua_user`** (the `administrator` user unless the
inventory names another user key). The `_dmarc` record publishes
`rua=mailto:<username>@<mail domain>`, and a deploy whose report user carries
no `mailbox` account fails before any record is written.
- **`config.json` is bootstrap-only** (data store selection); all other
configuration lives in the database and is provisioned over JMAP
(`templates/jmap/*.json.j2`).
- **Only authenticated sessions relay, with or without SSO.** Under SSO a bot
authenticates with an app password.
- **Address bans expire after `services.stalwart.ban_period_seconds`** (one
hour by default). Without a period Stalwart keeps a ban forever, and the
reverse proxy, the published ports, Tor and the swarm ingress hand many
clients one address.
- **Bans and failed logins also go to the container output**
(`STALWART_BAN_TRACER`, `tasks/tracing.yml`), next to the daily log file in
the data volume.
## Features
- All-in-one mail server (SMTP/IMAP/JMAP/POP3/ManageSieve)
- CalDAV / CardDAV / WebDAV collaboration
- Built-in spam filtering
- ClamAV antivirus as an SMTP DATA-stage milter (`services.clamav.enabled: false` for spam-only)
- DKIM signing with automatic key management; SPF / DMARC published in DNS
- OpenID Connect SSO via Keycloak
- Roundcube webmail
- PostgreSQL backing store
## Quick Setup
### Development
Clone, set up the workstation, and deploy Stalwart Mail Server onto the local stack:
```bash
git clone https://github.com/infinito-nexus/core.git
cd core
make onboard
make compose-deploy mode=reinstall apps=web-app-stalwart full_cycle=false
```
### Production
Run the published image to provision the inventory and deploy Stalwart Mail Server to a managed server (the mounted volume persists the inventory):
```bash
APP=web-app-stalwart
HOST=<your-server>
DOMAIN=<your-domain>
TLS_MODE=self_signed
SSH_PUBLIC_KEY="<your-ssh-public-key>"
docker run --rm -it \
-v "$PWD/inventories:/etc/infinito.nexus/inventories" \
-e APP="$APP" -e HOST="$HOST" -e DOMAIN="$DOMAIN" -e TLS_MODE="$TLS_MODE" -e SSH_PUBLIC_KEY="$SSH_PUBLIC_KEY" \
ghcr.io/infinito-nexus/core/debian bash -c '
INVENTORY=/etc/infinito.nexus/inventories/production
infinito administration inventory provision "$INVENTORY" \
--inventory-file "$INVENTORY/devices.yml" \
--host "$HOST" \
--include "$APP" \
--vars "{\"TLS_MODE\": \"$TLS_MODE\", \"DOMAIN_PRIMARY\": \"$DOMAIN\", \"users\": {\"administrator\": {\"authorized_keys\": [\"$SSH_PUBLIC_KEY\"]}}}" &&
infinito administration deploy dedicated "$INVENTORY/devices.yml" \
--password-file "$INVENTORY/.password" \
--diff -vv'
```
## Migration from Mailu
The provider cutover is an inventory change; mailbox data moves with it when the migration switch is on.
> **Compose only.** The import reads the legacy maildir volume on the stack host and submits over the host-published IMAPS port, neither of which holds under swarm. Migrate in compose mode, then move the stack to swarm.
1. Keep `web-app-mailu` in the host's groups and add `web-app-stalwart` — both MUST be present so Mailu re-renders as a legacy instance (`legacy-mail.<domain>`, no public mail ports) and releases `mail.<domain>` to Stalwart.
2. Remove `MAIL_PROVIDER` from the inventory (Stalwart is the default).
3. Set `applications["web-app-stalwart"].services.stalwart.migration.import_mailu: true` and run the full deploy. The role then reads Mailu's Dovecot Maildir volume and imports every inventory account's messages via IMAP APPEND, preserving folders, flags and internal dates. Re-runs are idempotent (Message-ID dedup), so the switch may stay on across deploys; turn it off once Mailu is retired.
The import authenticates per account with the inventory password, so it MUST run while `services.sso.enabled` is false. An OIDC directory replaces password login outright (see [`tasks/06_oidc.yml`](tasks/06_oidc.yml)), and every IMAP login then fails with `AUTHENTICATIONFAILED`. Migrate first, enable SSO afterwards.
4. Accounts and aliases are provisioned from the inventory by this role; mailboxes created only inside Mailu's admin UI MUST be added to the inventory first. Sieve filters and CalDAV/CardDAV data are out of scope.
5. Non-Cloudflare DNS: publish the new DKIM TXT record reported by the deploy; MX and A records keep their hostname.
The cutover is covered end to end by [`files/test/test.sh`](files/test/test.sh), which runs as this role's CLI test whenever `web-app-mailu` is co-deployed — matrix **variant 1**, the round where SSO is off, because the import authenticates with per-account passwords. The whole scenario runs inside the deployed host and needs nothing from the environment around it: it stores mail in both directions in the legacy Mailu, confirms it landed in the maildir volume, runs [`files/python/migrate_from_mailu.py`](files/python/migrate_from_mailu.py) — the same script and argv a real cutover uses — and then asserts over IMAP that the stored mail survived and that live mail still flows. No redeploy is involved; the cutover is a docker-level data move.
## Upgrading from 0.16
Stalwart 1.x refuses to open a 0.16 store and has no in-place upgrade. Every deploy checks the store in the role's database before it starts Stalwart, whatever state the running server is in, and stops when the store predates 1.0 ([`tasks/store_guard.yml`](tasks/store_guard.yml)). A store from before 1.0 keeps a `bigint` column `v` in table `u`, a 1.x store a `bytea` one, and a database without that column holds no store yet.
A deploy that has brought Stalwart 1.x up on the store and finished its provisioning writes the marker `store.layout`, holding the store layout version `1`, into the role's instance directory on the stack host (`STALWART_STORE_MARKER_FILE`, written last in [`tasks/manager_ops.yml`](tasks/manager_ops.yml)).
A failed deploy writes no marker.
A deploy that finds the marker passes without reading the store.
A deploy without the marker reads the store:
| Database | No store yet | Store to read |
|---|---|---|
| Shared PostgreSQL | the `postgres` superuser finds no database `stalwart` in the catalog | read as the role's database user |
| Dedicated PostgreSQL | the volume `stalwart_database` does not exist | read inside the dedicated database container; when that container is not running, the deploy stops and names the database service to start |
Migrate the store with [`stalwart-migrate`](https://github.com/stalwartlabs/stalwart-migrate) into a new database and swap it in under the role's database name. That name is fixed to `stalwart` ([`plugins/lookup/database.py`](../../plugins/lookup/database.py) derives it from the entity name), so the migration targets a second database that later takes over the name.
1. Make sure the server runs Stalwart `v0.16.27`; `stalwart-migrate` reads no other release. Upgrade an older 0.16 server with the previous revision of this role first.
2. Back up the database `stalwart` (for example `pg_dump -Fc -d stalwart -f stalwart-v016.dump`) and the role's volumes.
3. As a PostgreSQL superuser, create the empty target database, owned by the role's database user:
```sql
CREATE DATABASE stalwart_v1 OWNER stalwart;
```
4. Copy the rendered `config.json` (`STALWART_CONFIG_FILE`, `etc/config.json` in the role's volumes directory) into a new directory and set its `"database"` to `"stalwart_v1"`. This file is the `--target`.
5. Answer the conversion questions and copy the data while 0.16 keeps serving. Run the tool on the network the `stalwart` container reaches its database on (`docker inspect stalwart`), so the hosts in both files resolve:
```sh
docker run --rm -it --network <stalwart-network> \
-v <volumes-dir>/etc:/etc/stalwart:ro \
-v <target-dir>:/etc/stalwart-v1 \
-v <state-dir>:/var/lib/stalwart-migrate \
stalwartlabs/stalwart-migrate:1.0.0 prepare \
--source /etc/stalwart/config.json \
--state /var/lib/stalwart-migrate
```
Then run the same container with `run --source /etc/stalwart/config.json --target /etc/stalwart-v1/config.json --state /var/lib/stalwart-migrate`. `run` copies only what changed since the previous run and may be repeated.
6. Stop the Stalwart server (`docker stop stalwart` in compose, `docker service scale <stack>_stalwart=0` in swarm) and run the same container with `run --final` and the same options. It verifies the copy and writes `final-report.txt` into the state directory.
7. Swap the databases, as a PostgreSQL superuser connected to the `postgres` database:
```sql
ALTER DATABASE stalwart RENAME TO stalwart_v016;
ALTER DATABASE stalwart_v1 RENAME TO stalwart;
```
8. Deploy this role. The store guard finds the migrated 1.x store under the role's database name and lets Stalwart 1.x start on it.
9. Keep `stalwart_v016`, the dump and the state directory until 1.x is verified. `stalwart-migrate rollback` reads the state directory to copy the 1.x store back into a new 0.16 store.
### Restore and redeploy
The marker lives outside the stack and its volumes, so it survives `docker stack rm`, `docker compose down`, a crashed database and the stop and start cycle of `backup.project_hard_restart`.
A host that carries the marker therefore redeploys while its dedicated database is down, as in the restore of [`svc-bkp-nfs-2-local`](../svc-bkp-nfs-2-local/README.md) (`docker stack rm`, restore, redeploy).
A dedicated store on a host without the marker, such as a 0.16 host or a host whose instance directory was lost, needs its database running before the deploy: start the database service of the stack the host last deployed, then deploy.
Before a host that carries the marker goes back to a 0.16 store, through `stalwart-migrate rollback` or a backup taken under 0.16, delete the marker, so the next deploy reads the store.
## Verifying a production server
Deploying against a publicly reachable mail server additionally asserts that server's live **hard facts** — the records and listeners either match the deployed configuration or they do not. There is no mail-flow scenario here; that is what the suites above are for.
Set `INFINITO_MAIL_PRODUCTION_HOST` to the server's public FQDN (in CI, a GitHub repository variable of the same name; empty disables the whole check). Optionally set `INFINITO_MAIL_PRODUCTION_RESOLVER` to the address of a public resolver so the records are read from the outside view instead of `/etc/resolv.conf`, which matters on a host whose own resolver answers from a split-horizon zone.
[`files/python/production_facts.py`](files/python/production_facts.py) then checks, read-only:
| Fact | Assertion |
|---|---|
| A / AAAA | the mail host resolves |
| MX | the zone's only MX is the mail host (the role publishes it `solo`) |
| SPF | exactly one `v=spf1` record, authorising `mx` or `a:<mailhost>` |
| DMARC | `_dmarc` publishes a `v=DMARC1` record with a policy whose `rua` names the deployed aggregate report mailbox |
| DKIM | the selector this deploy read back publishes a non-empty `v=DKIM1` key |
| SRV | `_submissions`/465, `_imaps`/993, `_pop3s`/995 point at the mail host |
| PTR | rDNS does not contradict the mail host (absent → warning; rDNS is provisioned for Hetzner only) |
| SMTP | port 25 greets with `220` carrying the FQDN, proving the `rejectNonFqdn` identity |
The same variable points [`sys-ctl-mtn-cert-deploy`](../sys-ctl-mtn-cert-deploy/)'s remote check at `:465` and `:993`, so the live TLS chain and its remaining validity are verified alongside. A misconfigured production server therefore fails the deploy instead of surfacing as an outage.
## Further Reading
- [Stalwart documentation](https://stalw.art/docs)
- [`sys-svc-mail`](../sys-svc-mail/) — how applications send mail
- [`plugins/lookup/email.py`](../../plugins/lookup/email.py) — the email abstraction
> **Note:** Stalwart's JMAP object schema is version-sensitive. Pin
> `services.stalwart.version`; the provisioning payloads in `tasks/` were
> validated against that release's `GET /api/schema`.
## Credits
Implemented by **[Alejandro Roman Ibanez](https://github.com/AlejandroRomanIbanez)**.
Part of the [Infinito.Nexus Project](https://s.infinito.nexus/code) and maintained by [Kevin Veen-Birkenbach](https://www.veen.world).
Licensed under the [Infinito.Nexus Community License (Non-Commercial)](https://s.infinito.nexus/license).