dovecot: security backports, new versioning scheme

- Fix dovecot package download URLs for new
  [release](https://github.com/chatmail/dovecot/releases/tag/upstream%2F2.3.21%2Bdfsg1-3%2Bchatmail2)
  with
    - debian-security backport for 12 CVEs
    - distro-specific suffix (+deb{release}u1), enabling a simplified
      primary URL path and combined github releases
- Use VERSION_ID from os-release as deb_release instead of codename
  mapping, reorder hash-dict to match Github release page
- Remove redundant parsing/validation, let function validate against hash dict
- Update test expectations and test new versioning derivation

.github/workflows/ci-no-dns.yaml

@@ -0,0 +1,40 @@
+name: No-DNS
+
+on:
+  # Triggers when a PR is merged into main or a direct push occurs
+  push:
+    branches: [ "main" ]
+    
+  # Triggers for any PR (and its subsequent commits) targeting the main branch
+  pull_request:
+    branches: [ "main" ]
+
+permissions: {}
+
+# Newest push wins: Prevents multiple runs from clashing and wasting runner efforts
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+
+jobs:
+  no-dns:
+    name: LXC deploy and test
+    uses: chatmail/cmlxc/.github/workflows/lxc-test.yml@main
+    with:
+      cmlxc_version: main
+      cmlxc_commands: |
+        cmlxc init 
+        # single cmdeploy relay test
+        cmlxc -v deploy-cmdeploy --source ./repo --type ipv4 cm0
+        cmlxc -v test-cmdeploy cm0
+
+        # cross cmdeploy relay test (two ipv4 relays)
+        cmlxc -v deploy-cmdeploy --source ./repo --ipv4-only --type ipv4 cm1
+        cmlxc -v test-cmdeploy cm0 cm1
+
+        # cross cmdeploy/madmail relay tests
+        cmlxc -v deploy-madmail mad0
+        cmlxc -v test-cmdeploy cm0 mad0
+        cmlxc -v test-mini mad0 cm0
+        cmlxc -v test-mini cm0 mad0

.github/workflows/ci.yaml

@@ -1,4 +1,4 @@
-name: Run unit-tests and container-based deploy+test verification
+name: CI
 
 on:
   # Triggers when a PR is merged into main or a direct push occurs
@@ -29,7 +29,7 @@ jobs:
           ref: ${{ github.event.pull_request.head.sha }}
           persist-credentials: false
       - name: download filtermail
-        run: curl -L https://github.com/chatmail/filtermail/releases/download/v0.6.4/filtermail-x86_64 -o /usr/local/bin/filtermail && chmod +x /usr/local/bin/filtermail
+        run: curl -L https://github.com/chatmail/filtermail/releases/download/v0.7.4/filtermail-x86_64 -o /usr/local/bin/filtermail && chmod +x /usr/local/bin/filtermail
       - name: run chatmaild tests 
         working-directory: chatmaild
         run: pipx run tox
@@ -57,9 +57,9 @@ jobs:
 
   lxc-test:
     name: LXC deploy and test
-    uses: chatmail/cmlxc/.github/workflows/lxc-test.yml@v0.13.5
+    uses: chatmail/cmlxc/.github/workflows/lxc-test.yml@main
     with:
-      cmlxc_version: v0.13.5
+      cmlxc_version: main
       cmlxc_commands: |
         cmlxc init 
         # single cmdeploy relay test
@@ -76,3 +76,4 @@ jobs:
         cmlxc -v test-cmdeploy cm0 mad0
         cmlxc -v test-mini cm0 mad0
         cmlxc -v test-mini mad0 cm0
+

.github/workflows/docker-dispatch.yaml

@@ -8,7 +8,8 @@ name: Trigger Docker build
 
 on:
   push:
-    branches: [main]
+    branches: [main, j4n/dovecot-multidist]
+    tags: ['[0-9]+.[0-9]+.[0-9]+']
   workflow_dispatch:
 
 permissions: {}

.github/workflows/docs-preview.yaml

@@ -13,6 +13,11 @@ jobs:
   scripts:
     name: build 
     runs-on: ubuntu-latest
+    env:
+      # Pin the repository links in the docs to this pull request's head commit
+      # so that linkcheck resolves files which only exist on the branch so far.
+      # see doc/conf.py
+      DOC_GITHUB_REF: ${{ github.event.pull_request.head.sha }}
     environment:
       name: 'staging.chatmail.at/doc/relay/'
       url: https://staging.chatmail.at/doc/relay/${{ steps.prepare.outputs.prid }}
@@ -51,7 +56,7 @@ jobs:
           mkdir -p "$HOME/.ssh"
           echo "${{ secrets.CHATMAIL_STAGING_SSHKEY }}" > "$HOME/.ssh/key"
           chmod 600 "$HOME/.ssh/key"
-          rsync -rILvh -e "ssh -i $HOME/.ssh/key -o StrictHostKeyChecking=no" $GITHUB_WORKSPACE/doc/build/ "${{ secrets.USERNAME }}@chatmail.at:/var/www/html/staging.chatmail.at/doc/relay/${STEPS_PREPARE_OUTPUTS_PRID}/"
+          rsync -rILvh -e "ssh -i $HOME/.ssh/key -o StrictHostKeyChecking=no" $GITHUB_WORKSPACE/doc/build/ "${{ secrets.USERNAME }}@chatmail.at:${STEPS_PREPARE_OUTPUTS_PRID}/"
         env:
           STEPS_PREPARE_OUTPUTS_PRID: ${{ steps.prepare.outputs.prid }}
 

.github/workflows/docs.yaml

@@ -47,5 +47,5 @@ jobs:
           mkdir -p "$HOME/.ssh"
           echo "${{ secrets.CHATMAIL_STAGING_SSHKEY }}" > "$HOME/.ssh/key"
           chmod 600 "$HOME/.ssh/key"
-          rsync -rILvh -e "ssh -i $HOME/.ssh/key -o StrictHostKeyChecking=no" $GITHUB_WORKSPACE/doc/build/ "${{ secrets.USERNAME }}@chatmail.at:/var/www/html/chatmail.at/doc/relay/"
+          rsync -rILvh -e "ssh -i $HOME/.ssh/key -o StrictHostKeyChecking=no" $GITHUB_WORKSPACE/doc/build/ "${{ secrets.USERNAME }}@chatmail.at:"
 

CHANGELOG.md

@@ -1,4 +1,101 @@
-# Changelog for chatmail deployment 
+# Changelog for chatmail deployment
+
+## [1.12.0] - 2026-07-31
+
+### Breaking Changes
+
+- [**breaking**] Introduce configurable system limits to reject new address creation and limit imap/smtp connections.
+  Dovecot default connection limit lowered from 50k to 10k,
+  Postfix default connection limit lowered from 5k to 1k,
+  larger relays need to adjust their settings.
+
+### Features
+
+- Reduce maximal_queue_lifetime from 5d to 2d
+- Disable negative cache in unbound (#992)
+- *(mtail)* Add incoming_mailer_daemon_mail_count
+- *(postfix)* Disable processing of MIME headers
+- *(dovecot)* Advertise privacy_mail as admin contact, drop server comment
+
+### Bug Fixes
+
+- Set relay restrictions per smtpd service with default reject
+- Reduce maxproc for filtermail-transport LMTP client to 500
+- Core 2.50.0 does not have delete_server_after config anymore.
+- Check if all required ports are available for filtermail (#983)
+- Always deploy unbound.conf.d/chatmail.conf (#993)
+- Expire empty directories (#994)
+- Crypt-r dependency was declared for wrong Python version
+- Always overwrite /etc/resolv.conf, even if it is a symbolic link
+- Pass kwargs to files.put()
+- List Iroh proxy endpoints used by 0.35 and 1.0, drop stale /relay/probe from earlier versions
+- Fix port discovery when ss -tulpn shows dovecot before stats
+
+### Documentation
+
+- Add scripts/initenv.sh to upgrade instructions
+- Update overview diagrams (#995)
+- *(overview)* Remove mermaid styles from 'Accepting and delivering mail' (#1009)
+- *(README.md)* Clarify security enforcement (#1011)
+
+### Miscellaneous Tasks
+
+- *(ci)* Auto-trigger docker build on release tag push
+- *(acmetool)* Update let's encrypt ToS link to 1.8
+- *(ci)* Update doc staging upload path
+- *(ci)* Fix docs upload path
+
+### Refactor
+
+- *(postfix)* Remove unused "filter" lmtp service
+- Install dns-root-data instead of using unbound-anchor
+- *(deps)* Remove domain-validator dependency
+
+### Testing
+
+- Set socket security for IMAP and SMTP to "TLS" in "dclogin"
+
+## [1.11.0] - 2026-05-15
+
+### Breaking Changes
+
+- [**breaking**] Drop passthrough_sender and passthrough_recipients chatmail.ini options to eliminate one more source of unencrypted messages
+
+### Features
+
+- Use filtermail for delivery to remote MTAs
+- Expose metadata "maxsmtprecipients" value
+- Support setup without domain, with only an IPv4 address (#963)
+- *(doc/docker)* Introduce docker images in documentation
+- DKIM-sign bounce messages (mainly "user does not exist")
+- *(config)* Load default values from Config(), not chatmail.ini.f (#853)
+- Make turn_socket_path configurable, and cleanup tests and turnserver code.
+- Warn about any unused chatmail.ini parameter at the end of "cmdeploy run"
+
+### Bug Fixes
+
+- Make www tests work with editable instead of just plain installs
+- Use path with no leading slash for mxdeliv
+- Increase filtermail-transport concurrency limit
+- Fix #972 by increasing file descriptors for filtermail
+- *(mtail)* Correct boot ordering and deploy restart logic
+- *(cmdeploy)* Stop and disable unbound-resolvconf
+- *(nginx)* Properly redirect www to mail_domain
+- *(dns)* Query correct NS if MNAME server is hidden (#954)
+- Legacy token metadata storage used list type, but if no new setmetadata happened, the user would not be notified at all.
+- *(logging)* Log all http requests to syslog
+
+### Documentation
+
+- Document how to upgrade to new version (#965)
+
+### Other
+
+- *(deps)* Upgrade to filtermail v0.6.4
+
+### Refactor
+
+- Introduce automated change-tracking across deployers
 
 ## 1.10.0 2026-04-30
 

CONTRIBUTING.md

@@ -5,3 +5,6 @@ We use [git-cliff] to generate the changelog from commit messages before the rel
 
 [Conventional Commits]: https://www.conventionalcommits.org/
 [git-cliff]: https://git-cliff.org/
+
+To update client app version information,
+edit [chatmaild/src/chatmaild/defaults/appversions.json](chatmaild/src/chatmaild/defaults/appversions.json).

README.md

@@ -1,19 +1,24 @@
 
 # Chatmail relays for end-to-end encrypted email
 
-Chatmail relay servers are interoperable Mail Transport Agents (MTAs) designed for: 
+Chatmail relay servers are interoperable Mail Transport Agents (MTAs) designed for:
 
 -  **Zero State:** no private data or metadata collected, messages are auto-deleted, low disk usage
 
 -  **Instant/Realtime:** sub-second message delivery, realtime P2P
    streaming, privacy-preserving Push Notifications for Apple, Google, and Huawei;
 
--  **Security Enforcement**: only strict TLS, DKIM and OpenPGP with minimized metadata accepted
+-  **Security Enforcement**: Only connections with strict TLS are accepted;
+   all messages must be correctly signed with DKIM and OpenPGP-encrypted with minimized metadata.
+   There are experimental exceptions for no-DNS relays,
+   which are allowed use self-signed TLS certificates
+   and which do not need to DKIM-sign their messages.
+   Unencrypted messages are allowed in neither case.
 
 -  **Reliable Federation and Decentralization:** No spam or IP reputation checks, federating
    depends on established IETF standards and protocols.
 
-This repository contains everything needed to setup a ready-to-use chatmail relay on an ssh-reachable host. 
+This repository contains everything needed to setup a ready-to-use chatmail relay on an ssh-reachable host.
 For getting started and more information please refer to the web version of this repositories' documentation at
 
 [https://chatmail.at/doc/relay](https://chatmail.at/doc/relay)

RELEASE.md

@@ -1,15 +1,13 @@
 # Releasing a new version of chatmail relay
 
-For example, to release version 1.9.0 of chatmail relay, do the following steps.
+For example, to release version 1.13.0 of chatmail relay, do the following steps.
 
-1. Update the changelog: `git cliff --unreleased --tag 1.9.0 --prepend CHANGELOG.md` or `git cliff -u -t 1.9.0 -p CHANGELOG.md`.
+1. Update the changelog: `git cliff --unreleased --tag 1.13.0 --prepend CHANGELOG.md` or `git cliff -u -t 1.13.0 -p CHANGELOG.md`.
 
 2. Open the changelog in the editor, edit it if required.
 
 3. Commit the changes to the changelog with a commit message `chore(release): prepare for 1.9.0`.
 
-3. Tag the release: `git tag --annotate 1.9.0`.
+4. Open a PR with the new commit, merge it to main after review.
 
-4. Push the release tag: `git push origin 1.9.0`.
-
-5. Create a GitHub release: `gh release create 1.9.0`.
+5. In the web interface, create a GitHub release, tell it to create a new tag.

chatmaild/MANIFEST.in

@@ -1,3 +1,4 @@
+include src/chatmaild/defaults/*.json
 include src/chatmaild/ini/*.ini.f
 include src/chatmaild/ini/*.ini
 include src/chatmaild/tests/mail-data/*

chatmaild/pyproject.toml

@@ -8,8 +8,9 @@ version = "0.3"
 dependencies = [
   "iniconfig",
   "filelock",
+  "psutil",
   "requests",
-  "crypt-r >= 3.13.1 ; python_version >= '3.11'",
+  "crypt-r >= 3.13.1 ; python_version >= '3.13'",
 ]
 
 [tool.setuptools]
@@ -25,10 +26,6 @@ chatmail-expire = "chatmaild.expire:daily_expire_main"
 chatmail-quota-expire = "chatmaild.expire:quota_expire_main"
 chatmail-fsreport = "chatmaild.fsreport:main"
 lastlogin = "chatmaild.lastlogin:main"
-turnserver = "chatmaild.turnserver:main"
-
-[project.entry-points.pytest11]
-"chatmaild.testplugin" = "chatmaild.tests.plugin"
 
 [tool.pytest.ini_options]
 addopts = "-v -ra --strict-markers"

chatmaild/src/chatmaild/config.py

@@ -1,3 +1,4 @@
+import ipaddress
 from pathlib import Path
 
 import iniconfig
@@ -8,67 +9,89 @@ from chatmaild.user import User
 def read_config(inipath):
     assert Path(inipath).exists(), inipath
     cfg = iniconfig.IniConfig(inipath)
-    params = cfg.sections["params"]
-    default_config_content = get_default_config_content(params["mail_domain"])
-    df_params = iniconfig.IniConfig("ini", data=default_config_content)["params"]
-    new_params = dict(df_params.items())
-    new_params.update(params)
-    return Config(inipath, params=new_params)
+    return Config(inipath, params=cfg.sections["params"])
 
 
 class Config:
     def __init__(self, inipath, params):
         self._inipath = inipath
-        self.mail_domain = params["mail_domain"]
-        self.max_user_send_per_minute = int(params.get("max_user_send_per_minute", 60))
-        self.max_user_send_burst_size = int(params.get("max_user_send_burst_size", 10))
-        self.max_mailbox_size = params["max_mailbox_size"]
-        self.max_message_size = int(params.get("max_message_size", "31457280"))
-        self.delete_mails_after = params["delete_mails_after"]
-        self.delete_large_after = params["delete_large_after"]
-        self.delete_inactive_users_after = int(params["delete_inactive_users_after"])
-        self.username_min_length = int(params["username_min_length"])
-        self.username_max_length = int(params["username_max_length"])
-        self.password_min_length = int(params["password_min_length"])
-        self.passthrough_senders = params["passthrough_senders"].split()
-        self.passthrough_recipients = params["passthrough_recipients"].split()
-        self.www_folder = params.get("www_folder", "")
-        self.filtermail_smtp_port = int(params.get("filtermail_smtp_port", "10080"))
+        params = dict(params)
+        raw_domain = params.pop("mail_domain")
+        self.mail_domain_bare = raw_domain
+
+        if is_valid_ipv4(raw_domain):
+            self.ipv4_relay = raw_domain
+            self.mail_domain = f"[{raw_domain}]"
+            self.postfix_myhostname = ipaddress.IPv4Address(raw_domain).reverse_pointer
+        else:
+            self.ipv4_relay = None
+            self.mail_domain = raw_domain
+            self.postfix_myhostname = raw_domain
+
+        self.max_user_send_per_minute = int(params.pop("max_user_send_per_minute", 60))
+        self.max_user_send_burst_size = int(params.pop("max_user_send_burst_size", 10))
+        self.max_mailbox_size = params.pop("max_mailbox_size", "500M")
+        self.max_message_size = int(params.pop("max_message_size", 31457280))
+        self.delete_mails_after = params.pop("delete_mails_after", "20")
+        self.delete_large_after = params.pop("delete_large_after", "7")
+        self.delete_inactive_users_after = int(
+            params.pop("delete_inactive_users_after", 90)
+        )
+        self.username_min_length = int(params.pop("username_min_length", 9))
+        self.username_max_length = int(params.pop("username_max_length", 9))
+        self.password_min_length = int(params.pop("password_min_length", 9))
+        self.www_folder = params.pop("www_folder", "")
+        self.filtermail_smtp_port = int(params.pop("filtermail_smtp_port", "10080"))
         self.filtermail_smtp_port_incoming = int(
-            params.get("filtermail_smtp_port_incoming", "10081")
+            params.pop("filtermail_smtp_port_incoming", "10081")
         )
         self.filtermail_http_port_incoming = int(
-            params.get("filtermail_http_port_incoming", "10082")
+            params.pop("filtermail_http_port_incoming", "10082")
         )
         self.filtermail_lmtp_port_transport = int(
-            params.get("filtermail_lmtp_port_transport", "10083")
+            params.pop("filtermail_lmtp_port_transport", "10083")
         )
-        self.postfix_reinject_port = int(params.get("postfix_reinject_port", "10025"))
+        self.postfix_reinject_port = int(params.pop("postfix_reinject_port", "10025"))
         self.postfix_reinject_port_incoming = int(
-            params.get("postfix_reinject_port_incoming", "10026")
+            params.pop("postfix_reinject_port_incoming", "10026")
         )
-        self.mtail_address = params.get("mtail_address")
-        self.disable_ipv6 = params.get("disable_ipv6", "false").lower() == "true"
-        self.acme_email = params.get("acme_email", "")
-        self.imap_rawlog = params.get("imap_rawlog", "false").lower() == "true"
-        self.imap_compress = params.get("imap_compress", "false").lower() == "true"
-        if "iroh_relay" not in params:
-            self.iroh_relay = "https://" + params["mail_domain"]
+        self.doveauth_http_port = int(params.pop("doveauth_http_port", "10084"))
+        self.mtail_address = params.pop("mtail_address", None)
+        self.disable_ipv6 = params.pop("disable_ipv6", "false").lower() == "true"
+        self.acme_email = params.pop("acme_email", "")
+        self.imap_rawlog = params.pop("imap_rawlog", "false").lower() == "true"
+        self.imap_compress = params.pop("imap_compress", "false").lower() == "true"
+        self.turn_socket_path = params.pop(
+            "turn_socket_path", "/run/chatmail-turn/turn.socket"
+        )
+        iroh_relay = params.pop("iroh_relay", None)
+        if iroh_relay is None:
+            self.iroh_relay = "https://" + raw_domain
             self.enable_iroh_relay = True
         else:
-            self.iroh_relay = params["iroh_relay"].strip()
+            self.iroh_relay = iroh_relay.strip()
             self.enable_iroh_relay = False
-        self.privacy_postal = params.get("privacy_postal")
-        self.privacy_mail = params.get("privacy_mail")
-        self.privacy_pdo = params.get("privacy_pdo")
-        self.privacy_supervisor = params.get("privacy_supervisor")
+        self.privacy_postal = params.pop("privacy_postal", None)
+        self.privacy_mail = params.pop("privacy_mail", None)
+        self.privacy_pdo = params.pop("privacy_pdo", None)
+        self.privacy_supervisor = params.pop("privacy_supervisor", None)
+
+        self.max_load_1m = float(params.pop("max_load_1m", 5))
+        self.min_available_memory_mb = parse_size_mb(
+            params.pop("min_available_memory", "200M")
+        )
+        self.min_free_disk_space_mb = parse_size_mb(
+            params.pop("min_free_disk_space", "1G")
+        )
+        self.max_imap_connections = int(params.pop("max_imap_connections", 10000))
+        self.max_smtp_connections = int(params.pop("max_smtp_connections", 1000))
 
         # TLS certificate management.
         # If tls_external_cert_and_key is set, use externally managed certs.
         # Otherwise derived from the domain name:
         # - Domains starting with "_" use self-signed certificates
         # - All other domains use ACME.
-        external = params.get("tls_external_cert_and_key", "").strip()
+        external = params.pop("tls_external_cert_and_key", "").strip()
 
         if external:
             parts = external.split()
@@ -79,21 +102,22 @@ class Config:
                 )
             self.tls_cert_mode = "external"
             self.tls_cert_path, self.tls_key_path = parts
-        elif self.mail_domain.startswith("_"):
+        elif raw_domain.startswith("_") or self.ipv4_relay:
             self.tls_cert_mode = "self"
             self.tls_cert_path = "/etc/ssl/certs/mailserver.pem"
             self.tls_key_path = "/etc/ssl/private/mailserver.key"
         else:
             self.tls_cert_mode = "acme"
-            self.tls_cert_path = f"/var/lib/acme/live/{self.mail_domain}/fullchain"
-            self.tls_key_path = f"/var/lib/acme/live/{self.mail_domain}/privkey"
+            self.tls_cert_path = f"/var/lib/acme/live/{raw_domain}/fullchain"
+            self.tls_key_path = f"/var/lib/acme/live/{raw_domain}/privkey"
 
         # deprecated option
-        mbdir = params.get("mailboxes_dir", f"/home/vmail/mail/{self.mail_domain}")
+        mbdir = params.pop("mailboxes_dir", f"/home/vmail/mail/{raw_domain}")
         self.mailboxes_dir = Path(mbdir.strip())
 
         # old unused option (except for first migration from sqlite to maildir store)
-        self.passdb_path = Path(params.get("passdb_path", "/home/vmail/passdb.sqlite"))
+        self.passdb_path = Path(params.pop("passdb_path", "/home/vmail/passdb.sqlite"))
+        self._unused_keys = list(params)
 
     @property
     def max_mailbox_size_mb(self):
@@ -150,28 +174,13 @@ def get_default_config_content(mail_domain, **overrides):
     for name, value in extra.items():
         new_line = f"{name} = {value}"
         new_lines.append(new_line)
+    return "\n".join(new_lines)
 
-    content = "\n".join(new_lines)
 
-    # apply testrun privacy overrides
-
-    if mail_domain.endswith(".testrun.org"):
-        override_inipath = inidir.joinpath("override-testrun.ini")
-        privacy = iniconfig.IniConfig(override_inipath)["privacy"]
-        lines = []
-        for line in content.split("\n"):
-            for key, value in privacy.items():
-                value_lines = value.format(mail_domain=mail_domain).strip().split("\n")
-                if not line.startswith(f"{key} =") or not value_lines:
-                    continue
-                if len(value_lines) == 1:
-                    lines.append(f"{key} = {value}")
-                else:
-                    lines.append(f"{key} =")
-                    for vl in value_lines:
-                        lines.append(f"    {vl}")
-                break
-            else:
-                lines.append(line)
-        content = "\n".join(lines)
-    return content
+def is_valid_ipv4(address: str) -> bool:
+    """Check if a mail_domain is an IPv4 address."""
+    try:
+        ipaddress.IPv4Address(address)
+        return True
+    except ValueError:
+        return False

chatmaild/src/chatmaild/defaults/appversions.json

@@ -0,0 +1,15 @@
+{
+  "clients": [
+    {
+      "clientId": "deltachat",
+      "sources": [
+        {
+          "sourceId": "gplay",
+          "versionInteger": 757,
+          "versionString": "2.59.1",
+          "downloadUrl": "https://github.com/deltachat/deltachat-android/releases/download/v2.59.1/deltachat-gplay-release-2.59.1.apk"
+        }
+      ]
+    }
+  ]
+}

chatmaild/src/chatmaild/doveauth.py

@@ -1,10 +1,17 @@
-import json
+"""Create chatmail addresses on first login.
+
+Dovecot only asks us about addresses it does not already find in the mailbox:
+the auth.lua we deploy with dovecot (cmdeploy/src/cmdeploy/dovecot/auth.lua.j2)
+verifies existing users itself against a mailbox password file,
+and HTTP-POSTs everything else to the /create endpoint implemented in this module.
+"""
+
 import logging
 import os
 import re
 import sys
-
-import filelock
+import threading
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
 
 try:
     import crypt_r
@@ -12,8 +19,8 @@ except ImportError:
     import crypt as crypt_r
 
 from .config import Config, read_config
-from .dictproxy import DictProxy
 from .migrate_db import migrate_from_db_to_maildir
+from .syslimits import has_sufficient_resources
 
 NOCREATE_FILE = "/etc/chatmail-nocreate"
 VALID_LOCALPART_RE = re.compile(r"^[a-z0-9._-]+$")
@@ -63,107 +70,117 @@ def is_allowed_to_create(config: Config, user, cleartext_password) -> bool:
     return True
 
 
-def split_and_unescape(s):
-    """Split strings using double quote as a separator and backslash as escape character
-    into parts."""
-
-    out = ""
-    i = 0
-    while i < len(s):
-        c = s[i]
-        if c == "\\":
-            # Skip escape character.
-            i += 1
-
-            # This will raise IndexError if there is no character
-            # after escape character. This is expected
-            # as this is an invalid input.
-            out += s[i]
-        elif c == '"':
-            # Separator
-            yield out
-            out = ""
-        else:
-            out += c
-        i += 1
-    yield out
+def verify_password(stored, cleartext_password) -> bool:
+    if stored.startswith("{"):
+        stored = stored.split("}", 1)[1]
+    return crypt_r.crypt(cleartext_password, stored) == stored
 
 
-class AuthDictProxy(DictProxy):
+class DoveAuth:
     def __init__(self, config):
-        super().__init__()
         self.config = config
+        self.creation_lock = threading.Lock()
 
-    def handle_lookup(self, parts):
-        # Dovecot <2.3.17 has only one part,
-        # do not attempt to read any other parts for compatibility.
-        keyname = parts[0]
-
-        namespace, type, args = keyname.split("/", 2)
-        args = list(split_and_unescape(args))
-
+    def create_user(self, addr, cleartext_password) -> bool:
+        """Create the address, or verify the password if it exists already."""
         config = self.config
-        reply_command = "F"
-        res = ""
-        if namespace == "shared":
-            if type == "userdb":
-                user = args[0]
-                if user.endswith(f"@{config.mail_domain}"):
-                    res = self.lookup_userdb(user)
-                if res:
-                    reply_command = "O"
-                else:
-                    reply_command = "N"
-            elif type == "passdb":
-                user = args[1]
-                if user.endswith(f"@{config.mail_domain}"):
-                    res = self.lookup_passdb(user, cleartext_password=args[0])
-                if res:
-                    reply_command = "O"
-                else:
-                    reply_command = "N"
-        json_res = json.dumps(res) if res else ""
-        return f"{reply_command}{json_res}\n"
-
-    def handle_iterate(self, parts):
-        # example: I0\t0\tshared/userdb/
-        if parts[2] == "shared/userdb/":
-            result = "".join(
-                f"Oshared/userdb/{user}\t\n" for user in self.iter_userdb()
-            )
-            return f"{result}\n"
-
-    def iter_userdb(self) -> list:
-        """Get a list of all user addresses."""
-        return [x for x in os.listdir(self.config.mailboxes_dir) if "@" in x]
-
-    def lookup_userdb(self, addr):
-        return self.config.get_user(addr).get_userdb_dict()
-
-    def lookup_passdb(self, addr, cleartext_password):
-        user = self.config.get_user(addr)
-        userdata = user.get_userdb_dict()
-        if userdata:
-            return userdata
-        if not is_allowed_to_create(self.config, addr, cleartext_password):
-            return
-
-        lock = filelock.FileLock(str(user.password_path) + ".lock", timeout=5)
-        with lock:
-            userdata = user.get_userdb_dict()
-            if userdata:
-                return userdata
+        if not addr.endswith(f"@{config.mail_domain}"):
+            logging.warning("address not in mail domain: %r", addr)
+            return False
+        try:
+            user = config.get_user(addr)
+        except ValueError:
+            logging.warning("invalid address: %r", addr)
+            return False
+        with self.creation_lock:
+            passhash = user.get_password_hash()
+            if passhash is not None:
+                # a concurrent first login may have just created the address
+                return verify_password(passhash, cleartext_password)
+            if not is_allowed_to_create(config, addr, cleartext_password):
+                return False
+            if not has_sufficient_resources(config):
+                return False
             user.set_password(encrypt_password(cleartext_password))
-            print(f"Created address: {addr}", file=sys.stderr)
-        return user.get_userdb_dict()
+        # mtail counts created_accounts off this exact line
+        print(f"Created address: {addr}", file=sys.stderr)
+        return True
+
+
+class CreateHandler(BaseHTTPRequestHandler):
+    """Answer POST /create requests from dovecot's auth.lua, body `addr\\tpassword`.
+
+    The body must be UTF-8 and only the first tab separates the fields,
+    so a password may itself contain tabs.
+    Any non-UTF8 or \\0 bytes in the body fail the request.
+
+    Addresses are ASCII: dovecot refuses any login name outside its
+    auth_username_chars before auth.lua ever sees it.
+
+    Dovecot hands auth.lua the exact password bytes the client sent;
+    decoding and re-encoding UTF-8 is byte-identical,
+    so dovecot's password_verify later recomputes the same hash crypt() stores here.
+    """
+
+    protocol_version = "HTTP/1.1"  # dovecot's HTTP client reuses connections
+
+    max_body_len = 512  # an address and a password
+
+    def do_POST(self):
+        if self.path != "/create":
+            self.reply(404)
+            return
+        length = self.body_length()
+        if length is None:
+            self.reply(400)
+            return
+        body = self.rfile.read(length)
+        try:
+            addr, _, password = body.decode("utf-8").partition("\t")
+        except UnicodeDecodeError:
+            self.reply(400)
+            return
+        if "\0" in addr or "\0" in password:
+            self.reply(400)
+            return
+        self.reply(200 if self.server.doveauth.create_user(addr, password) else 403)
+
+    def body_length(self):
+        try:
+            length = int(self.headers["Content-Length"])
+        except (TypeError, ValueError):
+            return None
+        return length if 0 <= length <= self.max_body_len else None
+
+    def reply(self, status):
+        self.send_response(status)
+        self.send_header("Content-Length", "0")
+        if status != 200:
+            # Just close on any failure, as body might not be fully read.
+            # It's anyway cheap to re-establish http localhost without TLS.
+            self.send_header("Connection", "close")
+        self.end_headers()
+
+    def log_message(self, format, *args):
+        # the per-request access log would only duplicate our own stderr lines
+        pass
+
+
+class DoveAuthServer(ThreadingHTTPServer):
+    # a burst of first-time logins (e.g. from CI) must not overflow
+    # the accept queue, see https://github.com/chatmail/relay/issues/436
+    request_queue_size = 1000
+
+    def __init__(self, config, port):
+        super().__init__(("127.0.0.1", port), CreateHandler)
+        self.doveauth = DoveAuth(config)
 
 
 def main():
-    socket, cfgpath = sys.argv[1:]
+    (cfgpath,) = sys.argv[1:]
     config = read_config(cfgpath)
 
     migrate_from_db_to_maildir(config)
 
-    dictproxy = AuthDictProxy(config=config)
-
-    dictproxy.serve_forever_from_socket(socket)
+    server = DoveAuthServer(config, config.doveauth_http_port)
+    server.serve_forever()

chatmaild/src/chatmaild/expire.py

@@ -168,6 +168,16 @@ class Expiry:
         if mbox.last_login and mbox.last_login < cutoff_without_login:
             self.remove_mailbox(mbox.basedir)
             return
+        elif mbox.last_login is None:
+            try:
+                if not self.dry:
+                    os.rmdir(mbox.basedir)
+                    self.del_mboxes += 1
+            except OSError:
+                print_info(
+                    f"Skipped deleting {mbox.basedir}, doesn't have last_login but isn't empty"
+                )
+            return
 
         mboxname = os.path.basename(mbox.basedir)
         if self.verbose:
@@ -249,7 +259,7 @@ def daily_expire_main(args=None):
     args = parser.parse_args(args)
 
     config = read_config(args.chatmail_ini)
-    now = datetime.utcnow().timestamp()
+    now = time.time()
     if args.days:
         now = now - 86400 * int(args.days)
 

chatmaild/src/chatmaild/fsreport.py

@@ -27,6 +27,7 @@ to also write legacy metrics.py style output (default: /var/www/html/metrics):
 
 import os
 import tempfile
+import time
 from argparse import ArgumentParser
 from datetime import datetime
 
@@ -264,7 +265,7 @@ def main(args=None):
 
     config = read_config(args.chatmail_ini)
 
-    now = datetime.utcnow().timestamp()
+    now = time.time()
     if args.days:
         now = now - 86400 * int(args.days)
 

chatmaild/src/chatmaild/ini/chatmail.ini.f

@@ -12,42 +12,62 @@ mail_domain = {mail_domain}
 #
 
 # email sending rate per user and minute
-max_user_send_per_minute = 60
+#max_user_send_per_minute = 60
 
 # per-user max burst size for sending rate limiting (GCRA bucket capacity)
-max_user_send_burst_size = 10
+#max_user_send_burst_size = 10
 
 # maximum mailbox size of a chatmail address
-# Oldest messages will be removed automatically, so mailboxes never run full.
-max_mailbox_size = 500M
+# (Oldest messages will be removed automatically, so mailboxes never run full)
+#max_mailbox_size = 500M
 
 # maximum message size for an e-mail in bytes
-max_message_size = 31457280
+#max_message_size = 31457280
 
 # days after which mails are unconditionally deleted
-delete_mails_after = 20
+#delete_mails_after = 20
 
 # days after which large messages (>200k) are unconditionally deleted
-delete_large_after = 7
+#delete_large_after = 7
 
 # days after which users without a successful login are deleted (database and mails)
-delete_inactive_users_after = 90
+#delete_inactive_users_after = 90
 
 # minimum length a username must have
-username_min_length = 9
+#username_min_length = 9
 
 # maximum length a username can have
-username_max_length = 9
+#username_max_length = 9
 
 # minimum length a password must have
-password_min_length = 9
+#password_min_length = 9
 
-# list of chatmail addresses which can send outbound un-encrypted mail
-passthrough_senders =
+#
+# System resource limits
+#
 
-# list of e-mail recipients for which to accept outbound un-encrypted mails
-# (space-separated, item may start with "@" to whitelist whole recipient domains)
-passthrough_recipients =
+# The following three limits refuse creation of new addresses
+# while existing addresses keep working.
+# Rejections are logged by the doveauth service.
+
+# Maximum 1-minute load average, as reported by "uptime";
+# it counts processes waiting for disk I/O as well as for CPU.
+#max_load_1m = 5
+
+# Minimum memory available without swapping.
+#min_available_memory = 200M
+
+# Minimum free disk space on the file system holding the mailboxes.
+#min_free_disk_space = 1G
+
+# Maximum number of concurrent IMAP connections
+# (the Dovecot imap process limit).
+#max_imap_connections = 10000
+
+# Maximum number of concurrent SMTP connections
+# on each of the submission and smtps ports (the Postfix process limit).
+# A single client IP may use up to a fifth of this.
+#max_smtp_connections = 1000
 
 # Use externally managed TLS certificates instead of built-in acmetool.
 # Paths refer to files on the deployment server (not the build machine).
@@ -63,19 +83,11 @@ passthrough_recipients =
 # Deployment Details
 #
 
-# SMTP outgoing filtermail and reinjection 
-filtermail_smtp_port = 10080
-postfix_reinject_port = 10025
-
-# SMTP incoming filtermail and reinjection 
-filtermail_smtp_port_incoming = 10081
-postfix_reinject_port_incoming = 10026
-
 # if set to "True" IPv6 is disabled
-disable_ipv6 = False
+#disable_ipv6 = False
 
 # Your email adress, which will be used in acmetool to manage Let's Encrypt SSL certificates
-acme_email = 
+#acme_email =
 
 # Defaults to https://iroh.{{mail_domain}} and running `iroh-relay` on the chatmail
 # service.
@@ -108,13 +120,13 @@ acme_email =
 # in per-maildir ".in/.out" files. 
 # Note that you need to manually cleanup these files
 # so use this option with caution on production servers. 
-imap_rawlog = false 
+#imap_rawlog = false
 
 # set to true if you want to enable the IMAP COMPRESS Extension,
 # which allows IMAP connections to be efficiently compressed.
 # WARNING: Enabling this makes it impossible to hibernate IMAP
 # processes which will result in much higher memory/RAM usage.
-imap_compress = false
+#imap_compress = false
 
 
 #

chatmaild/src/chatmaild/ini/override-testrun.ini

@@ -1,16 +0,0 @@
-
-[privacy]
-
-passthrough_recipients = privacy@testrun.org echo@{mail_domain}
-
-privacy_postal =
-    Merlinux GmbH, Represented by the managing director H. Krekel,
-    Reichgrafen Str. 20, 79102 Freiburg, Germany
-
-privacy_mail = privacy@testrun.org
-privacy_pdo =
-    Prof. Dr. Fabian Schmieder, lexICT UG (limited), Ostfeldstr. 49, 30559 Hannover.
-    You can contact him at *delta-privacy@merlinux.eu* (Keyword: DPO)
-privacy_supervisor =
-    State Commissioner for Data Protection and Freedom of Information of
-    Baden-Württemberg in 70173 Stuttgart, Germany.

chatmaild/src/chatmaild/metadata.py

@@ -1,13 +1,35 @@
+import json
 import logging
+import socket
 import sys
 import time
 from contextlib import contextmanager
+from importlib.resources import files
 
 from .config import read_config
 from .dictproxy import DictProxy
 from .filedict import FileDict
 from .notifier import Notifier
-from .turnserver import turn_credentials
+
+
+def turn_credentials(turn_socket_path):
+    with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as client_socket:
+        client_socket.settimeout(5)
+        client_socket.connect(turn_socket_path)
+        with client_socket.makefile("rb") as file:
+            return file.readline().decode("utf-8").strip()
+
+
+def read_appversions(path):
+    try:
+        data = json.loads(path.read_bytes())
+    except FileNotFoundError:
+        return None
+    except (OSError, ValueError):
+        logging.exception(f"failed to read {path}")
+        return None
+    # the dict protocol is line-based, keep the value single-line
+    return json.dumps(data, separators=(",", ":"))
 
 
 def _is_valid_token_timestamp(timestamp, now):
@@ -79,38 +101,48 @@ class Metadata:
 
 
 class MetadataDictProxy(DictProxy):
-    def __init__(self, notifier, metadata, iroh_relay=None, turn_hostname=None):
+    def __init__(
+        self,
+        notifier,
+        metadata,
+        iroh_relay=None,
+        turn_hostname=None,
+        turn_socket_path=None,
+    ):
         super().__init__()
         self.notifier = notifier
         self.metadata = metadata
         self.iroh_relay = iroh_relay
         self.turn_hostname = turn_hostname
+        self.turn_socket_path = turn_socket_path
+        self.appversions_path = files(__package__).joinpath("defaults/appversions.json")
 
     def handle_lookup(self, parts):
         # Lpriv/43f5f508a7ea0366dff30200c15250e3/devicetoken\tlkj123poi@c2.testrun.org
-        keyparts = parts[0].split("/", 2)
-        if keyparts[0] == "priv":
-            keyname = keyparts[2]
-            addr = parts[1]
-            if keyname == self.metadata.DEVICETOKEN_KEY:
+        match parts[0].split("/", 2):
+            case ["priv", _, keyname] if keyname == self.metadata.DEVICETOKEN_KEY:
+                addr = parts[1]
                 res = " ".join(self.metadata.get_tokens_for_addr(addr))
                 return f"O{res}\n"
-        elif keyparts[0] == "shared":
-            keyname = keyparts[2]
-            if (
-                keyname == "vendor/vendor.dovecot/pvt/server/vendor/deltachat/irohrelay"
-                and self.iroh_relay
-            ):
-                # Handle `GETMETADATA "" /shared/vendor/deltachat/irohrelay`
-                return f"O{self.iroh_relay}\n"
-            elif keyname == "vendor/vendor.dovecot/pvt/server/vendor/deltachat/turn":
-                try:
-                    res = turn_credentials()
-                except Exception:
-                    logging.exception("failed to get TURN credentials")
-                    return "N\n"
-                port = 3478
-                return f"O{self.turn_hostname}:{port}:{res}\n"
+            case ["shared", _, keyname]:
+                prefix = "vendor/vendor.dovecot/pvt/server/vendor/deltachat/"
+                if keyname.startswith(prefix):
+                    match keyname[len(prefix) :]:
+                        case "irohrelay" if self.iroh_relay:
+                            return f"O{self.iroh_relay}\n"
+                        case "turn":
+                            try:
+                                res = turn_credentials(self.turn_socket_path)
+                            except Exception:
+                                logging.exception("failed to get TURN credentials")
+                                return "N\n"
+                            return f"O{self.turn_hostname}:3478:{res}\n"
+                        case "maxsmtprecipients":
+                            # postfix default  (see "postconf smtpd_recipient_limit")
+                            return "O1000\n"
+                        case "appversions":
+                            value = read_appversions(self.appversions_path)
+                            return f"O{value}\n" if value else "N\n"
 
         logging.warning(f"lookup ignored: {parts!r}")
         return "N\n"
@@ -120,12 +152,13 @@ class MetadataDictProxy(DictProxy):
         # https://github.com/dovecot/core/blob/main/src/lib-storage/mailbox-attribute.h
         keyname = parts[1].split("/")
         value = parts[2] if len(parts) > 2 else ""
-        if keyname[0] == "priv" and keyname[2] == self.metadata.DEVICETOKEN_KEY:
-            self.metadata.add_token_to_addr(addr, value)
-            return True
-        elif keyname[0] == "priv" and keyname[2] == "messagenew":
-            self.notifier.new_message_for_addr(addr, self.metadata)
-            return True
+        match keyname:
+            case ["priv", _, key] if key == self.metadata.DEVICETOKEN_KEY:
+                self.metadata.add_token_to_addr(addr, value)
+                return True
+            case ["priv", _, "messagenew"]:
+                self.notifier.new_message_for_addr(addr, self.metadata)
+                return True
 
         return False
 
@@ -136,6 +169,7 @@ def main():
     config = read_config(config_path)
     iroh_relay = config.iroh_relay
     mail_domain = config.mail_domain
+    socket_path = config.turn_socket_path
 
     vmail_dir = config.mailboxes_dir
     if not vmail_dir.exists():
@@ -153,6 +187,7 @@ def main():
         metadata=metadata,
         iroh_relay=iroh_relay,
         turn_hostname=mail_domain,
+        turn_socket_path=socket_path,
     )
 
     dictproxy.serve_forever_from_socket(socket)

chatmaild/src/chatmaild/newemail.py

@@ -2,7 +2,6 @@
 
 """CGI script for creating new accounts."""
 
-import ipaddress
 import json
 import secrets
 import string
@@ -15,16 +14,6 @@ ALPHANUMERIC = string.ascii_lowercase + string.digits
 ALPHANUMERIC_PUNCT = string.ascii_letters + string.digits + string.punctuation
 
 
-def wrap_ip(host):
-    if host.startswith("[") and host.endswith("]"):
-        return host
-    try:
-        ipaddress.ip_address(host)
-        return f"[{host}]"
-    except ValueError:
-        return host
-
-
 def create_newemail_dict(config: Config):
     user = "".join(
         secrets.choice(ALPHANUMERIC) for _ in range(config.username_max_length)
@@ -33,16 +22,22 @@ def create_newemail_dict(config: Config):
         secrets.choice(ALPHANUMERIC_PUNCT)
         for _ in range(config.password_min_length + 3)
     )
-    return dict(email=f"{user}@{wrap_ip(config.mail_domain)}", password=f"{password}")
+    return dict(email=f"{user}@{config.mail_domain}", password=f"{password}")
 
 
-def create_dclogin_url(email, password):
+def create_dclogin_url(config, email, password):
     """Build a dclogin: URL with credentials and self-signed cert acceptance.
 
     Uses ic=3 (AcceptInvalidCertificates) so chatmail clients
     can connect to servers with self-signed TLS certificates.
     """
-    return f"dclogin:{quote(email, safe='@')}?p={quote(password, safe='')}&v=1&ic=3"
+    if config.ipv4_relay:
+        imap_host = "&ih=" + config.ipv4_relay
+        smtp_host = "&sh=" + config.ipv4_relay
+    else:
+        imap_host = ""
+        smtp_host = ""
+    return f"dclogin:{quote(email, safe='@[]')}?p={quote(password, safe='')}&v=1{imap_host}{smtp_host}&ic=3"
 
 
 def print_new_account():
@@ -51,7 +46,9 @@ def print_new_account():
 
     result = dict(email=creds["email"], password=creds["password"])
     if config.tls_cert_mode == "self":
-        result["dclogin_url"] = create_dclogin_url(creds["email"], creds["password"])
+        result["dclogin_url"] = create_dclogin_url(
+            config, creds["email"], creds["password"]
+        )
 
     print("Content-Type: application/json")
     print("")

chatmaild/src/chatmaild/syslimits.py

@@ -0,0 +1,32 @@
+"""Detect whether the system is at its limits."""
+
+import logging
+
+import psutil
+
+MB = 1024 * 1024
+
+
+def read_value(getter):
+    try:
+        return getter()
+    except Exception as e:
+        logging.warning("ignoring unreadable system limit: %s", e)
+        return None
+
+
+def has_sufficient_resources(config):
+    """Return False if load, memory or disk exceeds a configured limit."""
+    load = read_value(lambda: psutil.getloadavg()[0])
+    mem = read_value(lambda: psutil.virtual_memory().available // MB)
+    disk = read_value(lambda: psutil.disk_usage(str(config.mailboxes_dir)).free // MB)
+    if load is not None and load > config.max_load_1m:
+        msg = f"load avg {load:.2f} > {config.max_load_1m:.2f}"
+    elif mem is not None and mem < config.min_available_memory_mb:
+        msg = f"available memory {mem}MB < {config.min_available_memory_mb}MB"
+    elif disk is not None and disk < config.min_free_disk_space_mb:
+        msg = f"free disk {disk}MB < {config.min_free_disk_space_mb}MB"
+    else:
+        return True
+    logging.warning("registration rejected: %s", msg)
+    return False

chatmaild/src/chatmaild/tests/conftest.py

@@ -0,0 +1,3 @@
+"""Opt in to the chatmaild fixtures, which are not registered globally."""
+
+from chatmaild.tests.plugin import *  # noqa: F403

chatmaild/src/chatmaild/tests/plugin.py

@@ -20,6 +20,10 @@ def make_config(tmp_path):
         basedir.mkdir(parents=True, exist_ok=True)
         overrides = settings.copy() if settings else {}
         overrides["mailboxes_dir"] = str(basedir)
+        # permissive resource limits so tests never depend on host load/memory/disk
+        overrides.setdefault("max_load_1m", "99999")
+        overrides.setdefault("min_available_memory", "0")
+        overrides.setdefault("min_free_disk_space", "0")
         write_initial_config(inipath, mail_domain, overrides=overrides)
         return read_config(inipath)
 
@@ -32,22 +36,27 @@ def example_config(make_config):
 
 
 @pytest.fixture
-def maildomain(example_config):
+def ipv4_config(make_config):
+    return make_config("1.3.3.7")
+
+
+@pytest.fixture
+def example_maildomain(example_config):
     return example_config.mail_domain
 
 
 @pytest.fixture
-def testaddr(maildomain):
-    return f"user.name@{maildomain}"
+def testaddr(example_maildomain):
+    return f"user.name@{example_maildomain}"
 
 
 @pytest.fixture
-def gencreds(maildomain):
+def example_gencreds(example_maildomain):
     count = itertools.count()
     next(count)
 
     def gen(domain=None):
-        domain = domain if domain else maildomain
+        domain = domain if domain else example_maildomain
         while 1:
             num = next(count)
             alphanumeric = "abcdefghijklmnopqrstuvwxyz1234567890"

chatmaild/src/chatmaild/tests/test_appversions.py

@@ -0,0 +1,96 @@
+import json
+
+import pytest
+
+from chatmaild.metadata import MetadataDictProxy
+
+ALLOWED_URL_PREFIXES = (
+    "https://github.com/deltachat/",
+    "https://download.delta.chat/",
+)
+
+
+def check_string(value):
+    assert isinstance(value, str), value
+    assert value
+
+
+def check_version_integer(value):
+    # core parses this as u32, see https://github.com/chatmail/core/pull/8557
+    assert isinstance(value, int) and not isinstance(value, bool), value
+    assert 0 <= value < 2**32, value
+
+
+def check_appversions(data):
+    """Verifies the file the way core parses it.
+
+    core deserializes into typed structs and drops the whole payload
+    of a relay if a single value has an unexpected type,
+    while missing or misspelled keys silently turn into defaults.
+    """
+    assert set(data) == {"clients"}, data
+    assert isinstance(data["clients"], list)
+    assert data["clients"]
+    client_ids = []
+    for client in data["clients"]:
+        assert set(client) == {"clientId", "sources"}, client
+        check_string(client["clientId"])
+        client_ids.append(client["clientId"])
+        assert isinstance(client["sources"], list)
+        assert client["sources"]
+        source_ids = []
+        for source in client["sources"]:
+            assert set(source) == {
+                "sourceId",
+                "versionInteger",
+                "versionString",
+                "downloadUrl",
+            }, source
+            check_string(source["sourceId"])
+            source_ids.append(source["sourceId"])
+            check_version_integer(source["versionInteger"])
+            check_string(source["versionString"])
+            check_string(source["downloadUrl"])
+            assert source["downloadUrl"].startswith(ALLOWED_URL_PREFIXES)
+        # core takes the first matching source, later duplicates never surface
+        assert len(set(source_ids)) == len(source_ids), source_ids
+    assert len(set(client_ids)) == len(client_ids), client_ids
+
+
+@pytest.fixture
+def appversions():
+    # check the file which chatmail-metadata actually serves
+    path = MetadataDictProxy(notifier=None, metadata=None).appversions_path
+    return json.loads(path.read_text())
+
+
+def test_appversions_schema(appversions):
+    check_appversions(appversions)
+
+
+@pytest.mark.parametrize("value", [True, -1, 2**32, "754", 754.0, None])
+def test_version_integer_rejected(appversions, value):
+    appversions["clients"][0]["sources"][0]["versionInteger"] = value
+    with pytest.raises(AssertionError):
+        check_appversions(appversions)
+
+
+@pytest.mark.parametrize("key", ["clientId", "sources"])
+def test_misspelled_client_key_rejected(appversions, key):
+    client = appversions["clients"][0]
+    client[key + "s"] = client.pop(key)
+    with pytest.raises(AssertionError):
+        check_appversions(appversions)
+
+
+def test_duplicate_source_id_rejected(appversions):
+    sources = appversions["clients"][0]["sources"]
+    sources.append(dict(sources[0]))
+    with pytest.raises(AssertionError):
+        check_appversions(appversions)
+
+
+def test_foreign_download_url_rejected(appversions):
+    appversions["clients"][0]["sources"][0]["downloadUrl"] = "https://example.org/x.apk"
+    with pytest.raises(AssertionError):
+        check_appversions(appversions)

chatmaild/src/chatmaild/tests/test_config.py

@@ -1,6 +1,10 @@
 import pytest
 
-from chatmaild.config import parse_size_mb, read_config
+from chatmaild.config import (
+    is_valid_ipv4,
+    parse_size_mb,
+    read_config,
+)
 
 
 def test_read_config_basic(example_config):
@@ -9,38 +13,46 @@ def test_read_config_basic(example_config):
     assert not example_config.privacy_pdo and not example_config.privacy_postal
 
     inipath = example_config._inipath
-    inipath.write_text(inipath.read_text().replace("60", "37"))
+    inipath.write_text(
+        inipath.read_text().replace(
+            "#max_user_send_per_minute = 60",
+            "max_user_send_per_minute = 37",
+        )
+    )
     example_config = read_config(inipath)
     assert example_config.max_user_send_per_minute == 37
     assert example_config.mail_domain == "chat.example.org"
+    assert example_config.ipv4_relay is None
 
 
-def test_read_config_basic_using_defaults(tmp_path, maildomain):
+def test_read_config_ipv4(ipv4_config):
+    assert ipv4_config.ipv4_relay == "1.3.3.7"
+    assert ipv4_config.mail_domain == "[1.3.3.7]"
+
+
+def test_read_config_basic_using_defaults(tmp_path, example_maildomain):
     inipath = tmp_path.joinpath("chatmail.ini")
-    inipath.write_text(f"[params]\nmail_domain = {maildomain}")
+    inipath.write_text(f"[params]\nmail_domain = {example_maildomain}")
     example_config = read_config(inipath)
     assert example_config.max_user_send_per_minute == 60
     assert example_config.filtermail_smtp_port_incoming == 10081
+    assert example_config.filtermail_smtp_port == 10080
+    assert example_config.postfix_reinject_port == 10025
+    assert example_config.max_user_send_per_minute == 60
+    assert example_config.max_mailbox_size == "500M"
+    assert example_config.delete_mails_after == "20"
+    assert example_config.delete_large_after == "7"
+    assert example_config.username_min_length == 9
+    assert example_config.username_max_length == 9
+    assert example_config.password_min_length == 9
+    assert example_config.max_imap_connections == 10000
+    assert example_config.max_smtp_connections == 1000
+    assert example_config._unused_keys == []
 
 
-def test_read_config_testrun(make_config):
-    config = make_config("something.testrun.org")
-    assert config.mail_domain == "something.testrun.org"
-    assert len(config.privacy_postal.split("\n")) > 1
-    assert len(config.privacy_supervisor.split("\n")) > 1
-    assert len(config.privacy_pdo.split("\n")) > 1
-    assert config.privacy_mail == "privacy@testrun.org"
-    assert config.filtermail_smtp_port == 10080
-    assert config.postfix_reinject_port == 10025
-    assert config.max_user_send_per_minute == 60
-    assert config.max_mailbox_size == "500M"
-    assert config.delete_mails_after == "20"
-    assert config.delete_large_after == "7"
-    assert config.username_min_length == 9
-    assert config.username_max_length == 9
-    assert config.password_min_length == 9
-    assert "privacy@testrun.org" in config.passthrough_recipients
-    assert config.passthrough_senders == []
+def test_config_unused_keys(make_config):
+    config = make_config("chat.example.org", {"passthrough_senders": "x@y.org"})
+    assert config._unused_keys == ["passthrough_senders"]
 
 
 def test_config_userstate_paths(make_config, tmp_path):
@@ -135,3 +147,17 @@ def test_max_mailbox_size_mb(make_config):
     config = make_config("chat.example.org")
     assert config.max_mailbox_size == "500M"
     assert config.max_mailbox_size_mb == 500
+
+
+@pytest.mark.parametrize(
+    ["input", "result"],
+    [
+        ("example.org", False),
+        ("1.3.3.7", True),
+        ("fe::1", False),
+        ("ad.1e.dag.adf", False),
+        ("12394142", False),
+    ],
+)
+def test_is_valid_ipv4(input, result):
+    assert result == is_valid_ipv4(input)

chatmaild/src/chatmaild/tests/test_delete_inactive_users.py

@@ -1,6 +1,6 @@
 import time
 
-from chatmaild.doveauth import AuthDictProxy
+from chatmaild.doveauth import DoveAuth
 from chatmaild.expire import daily_expire_main as main_expire
 
 
@@ -18,10 +18,10 @@ def test_login_timestamps(example_config):
 def test_delete_inactive_users(example_config):
     new = time.time()
     old = new - (example_config.delete_inactive_users_after * 86400) - 1
-    dictproxy = AuthDictProxy(example_config)
+    doveauth = DoveAuth(example_config)
 
     def create_user(addr, last_login):
-        dictproxy.lookup_passdb(addr, "q9mr3faue")
+        doveauth.create_user(addr, "q9mr3faue")
         user = example_config.get_user(addr)
         user.maildir.joinpath("cur").mkdir()
         user.maildir.joinpath("cur", "something").mkdir()

chatmaild/src/chatmaild/tests/test_doveauth.py

@@ -1,42 +1,37 @@
-import io
-import json
-import queue
+import http.client
 import threading
-import traceback
+from concurrent.futures import ThreadPoolExecutor
 
 import pytest
 
 import chatmaild.doveauth
 from chatmaild.doveauth import (
-    AuthDictProxy,
+    CreateHandler,
+    DoveAuth,
+    DoveAuthServer,
     is_allowed_to_create,
 )
 from chatmaild.newemail import create_newemail_dict
 
 
 @pytest.fixture
-def dictproxy(example_config):
-    return AuthDictProxy(config=example_config)
+def doveauth(example_config):
+    return DoveAuth(example_config)
 
 
-def test_basic(dictproxy, gencreds):
-    addr, password = gencreds()
-    dictproxy.lookup_passdb(addr, password)
-    data = dictproxy.lookup_userdb(addr)
-    assert data
-    data2 = dictproxy.lookup_passdb(addr, password)
-    assert data == data2
+def stored_hash(config, addr):
+    return config.get_user(addr).get_password_hash()
 
 
-def test_iterate_addresses(dictproxy):
-    addresses = []
+def test_basic(doveauth, example_config, example_gencreds):
+    addr, password = example_gencreds()
+    assert doveauth.create_user(addr, password)
+    passhash = stored_hash(example_config, addr)
+    assert passhash.startswith("{SHA512-CRYPT}")
 
-    for i in range(10):
-        addresses.append(f"asdf1234{i}@chat.example.org")
-        dictproxy.lookup_passdb(addresses[-1], "q9mr3faue")
-
-    res = dictproxy.iter_userdb()
-    assert set(res) == set(addresses)
+    # a second login verifies against the stored hash and rewrites nothing
+    assert doveauth.create_user(addr, password)
+    assert stored_hash(example_config, addr) == passhash
 
 
 def test_invalid_username_length(example_config):
@@ -53,75 +48,32 @@ def test_invalid_username_length(example_config):
     )
 
 
-def test_dont_overwrite_password_on_wrong_login(dictproxy):
-    """Test that logging in with a different password doesn't create a new user"""
-    res = dictproxy.lookup_passdb(
-        "newuser12@chat.example.org", "kajdlkajsldk12l3kj1983"
-    )
-    assert res["password"]
-    res2 = dictproxy.lookup_passdb("newuser12@chat.example.org", "kajdslqwe")
-    # this function always returns a password hash, which is actually compared by dovecot.
-    assert res["password"] == res2["password"]
+def test_dont_overwrite_password_on_wrong_login(doveauth, example_config):
+    addr = "newuser12@chat.example.org"
+    assert doveauth.create_user(addr, "kajdlkajsldk12l3kj1983")
+    passhash = stored_hash(example_config, addr)
+
+    assert not doveauth.create_user(addr, "kajdslqwe")
+    assert stored_hash(example_config, addr) == passhash
+
+    assert doveauth.create_user(addr, "kajdlkajsldk12l3kj1983")
+    assert stored_hash(example_config, addr) == passhash
 
 
-def test_nocreate_file(monkeypatch, tmpdir, dictproxy):
+def test_foreign_domain_is_refused(doveauth):
+    assert not doveauth.create_user("newuser12@evil.example.org", "qlwkejqlwe12")
+
+
+def test_nocreate_file(monkeypatch, tmpdir, doveauth, example_config):
     p = tmpdir.join("nocreate")
     p.write("")
     monkeypatch.setattr(chatmaild.doveauth, "NOCREATE_FILE", str(p))
-    dictproxy.lookup_passdb("newuser12@chat.example.org", "zequ0Aimuchoodaechik")
-    assert not dictproxy.lookup_userdb("newuser12@chat.example.org")
-
-
-def test_handle_dovecot_request(dictproxy):
-    transactions = {}
-    # Test that password can contain ", ', \ and /
-    msg = (
-        'Lshared/passdb/laksjdlaksjdlak\\\\sjdlk\\"12j\\\'3l1/k2j3123"'
-        "some42123@chat.example.org\tsome42123@chat.example.org"
-    )
-    res = dictproxy.handle_dovecot_request(msg, transactions)
-    assert res
-    assert res[0] == "O" and res.endswith("\n")
-    userdata = json.loads(res[1:].strip())
-    assert userdata["home"].endswith("chat.example.org/some42123@chat.example.org")
-    assert userdata["uid"] == userdata["gid"] == "vmail"
-    assert userdata["password"].startswith("{SHA512-CRYPT}")
-
-
-def test_handle_dovecot_protocol_hello_is_skipped(example_config, caplog):
-    dictproxy = AuthDictProxy(config=example_config)
-    rfile = io.BytesIO(b"H3\t2\t0\t\tauth\n")
-    wfile = io.BytesIO()
-    dictproxy.loop_forever(rfile, wfile)
-    assert wfile.getvalue() == b""
-    assert not caplog.messages
-
-
-def test_handle_dovecot_protocol_user_not_exists(example_config):
-    dictproxy = AuthDictProxy(config=example_config)
-    rfile = io.BytesIO(
-        b"H3\t2\t0\t\tauth\nLshared/userdb/foobar@chat.example.org\tfoobar@chat.example.org\n"
-    )
-    wfile = io.BytesIO()
-    dictproxy.loop_forever(rfile, wfile)
-    assert wfile.getvalue() == b"N\n"
-
-
-def test_handle_dovecot_protocol_iterate(gencreds, example_config):
-    dictproxy = AuthDictProxy(config=example_config)
-    dictproxy.lookup_passdb("asdf00000@chat.example.org", "q9mr3faue")
-    dictproxy.lookup_passdb("asdf11111@chat.example.org", "q9mr3faue")
-    rfile = io.BytesIO(b"H3\t2\t0\t\tauth\nI0\t0\tshared/userdb/")
-    wfile = io.BytesIO()
-    dictproxy.loop_forever(rfile, wfile)
-    lines = wfile.getvalue().decode("ascii").split("\n")
-    assert "Oshared/userdb/asdf00000@chat.example.org\t" in lines
-    assert "Oshared/userdb/asdf11111@chat.example.org\t" in lines
-    assert not lines[2]
+    addr = "newuser12@chat.example.org"
+    assert not doveauth.create_user(addr, "zequ0Aimuchoodaechik")
+    assert stored_hash(example_config, addr) is None
 
 
 def test_invalid_localpart_characters(make_config):
-    """Test that is_allowed_to_create rejects localparts with invalid characters."""
     config = make_config("chat.example.org", {"username_min_length": "3"})
     password = "zequ0Aimuchoodaechik"
     domain = config.mail_domain
@@ -141,64 +93,150 @@ def test_invalid_localpart_characters(make_config):
     assert not is_allowed_to_create(config, f"ab@cdef@{domain}", password)
     assert not is_allowed_to_create(config, f"abc/def@{domain}", password)
     assert not is_allowed_to_create(config, f"abc\\def@{domain}", password)
+    assert not is_allowed_to_create(config, f"üser123@{domain}", password)
 
 
-def test_concurrent_creation_same_account(dictproxy):
-    """Test that concurrent creation of the same account doesn't corrupt password."""
+def test_concurrent_creation_same_account(doveauth, example_config, capsys):
     addr = "racetest1@chat.example.org"
     password = "zequ0Aimuchoodaechik"
-    num_threads = 10
-    results = queue.Queue()
 
-    def create():
-        try:
-            res = dictproxy.lookup_passdb(addr, password)
-            results.put(("ok", res))
-        except Exception:
-            results.put(("err", traceback.format_exc()))
-
-    threads = [threading.Thread(target=create, daemon=True) for _ in range(num_threads)]
-    for t in threads:
-        t.start()
-    for t in threads:
-        t.join(timeout=10)
-
-    passwords_seen = set()
-    for _ in range(num_threads):
-        status, res = results.get()
-        if status == "err":
-            pytest.fail(f"concurrent creation failed\n{res}")
-        passwords_seen.add(res["password"])
+    def create(_):
+        ok = doveauth.create_user(addr, password)
+        return ok, stored_hash(example_config, addr)
 
+    with ThreadPoolExecutor(10) as pool:
+        results = list(pool.map(create, range(10)))
+    assert all(ok for ok, _ in results)
     # all threads must see the same password hash
-    assert len(passwords_seen) == 1
+    assert len({passhash for _, passhash in results}) == 1
+    assert capsys.readouterr().err.count("Created address:") == 1
 
 
-def test_50_concurrent_lookups_different_accounts(gencreds, dictproxy):
-    num_threads = 50
-    req_per_thread = 5
-    results = queue.Queue()
+def test_insufficient_resources_block_creation_not_existing_logins(
+    doveauth, example_gencreds, monkeypatch
+):
+    addr, password = example_gencreds()
+    assert doveauth.create_user(addr, password)
 
-    def lookup():
-        for i in range(req_per_thread):
-            addr, password = gencreds()
+    monkeypatch.setattr(
+        chatmaild.doveauth, "has_sufficient_resources", lambda config: False
+    )
+    newaddr, newpassword = example_gencreds()
+    assert not doveauth.create_user(newaddr, newpassword)
+    assert doveauth.create_user(addr, password)
+
+
+class TestHttpPost:
+    @pytest.fixture
+    def doveauth_server(self, example_config):
+        server = DoveAuthServer(example_config, port=0)
+        threading.Thread(target=server.serve_forever, daemon=True).start()
+        yield f"127.0.0.1:{server.server_address[1]}"
+        server.shutdown()
+        server.server_close()
+
+    @pytest.fixture
+    def post(self, doveauth_server):
+        def post(path, data):
+            conn = http.client.HTTPConnection(doveauth_server, timeout=10)
             try:
-                dictproxy.lookup_passdb(addr, password)
-            except Exception:
-                results.put(traceback.format_exc())
-            else:
-                results.put(None)
+                return self.post_on(conn, path, data).status
+            finally:
+                conn.close()
 
-    threads = []
-    for i in range(num_threads):
-        thread = threading.Thread(target=lookup, daemon=True)
-        threads.append(thread)
+        return post
 
-    print(f"created {num_threads} threads, starting them and waiting for results")
-    for thread in threads:
-        thread.start()
+    @pytest.fixture
+    def connection(self, doveauth_server):
+        """One kept-alive connection, which is all dovecot's HTTP client opens."""
+        conn = http.client.HTTPConnection(doveauth_server, timeout=10)
+        yield conn
+        conn.close()
 
-    for i in range(num_threads * req_per_thread):
-        res = results.get()
-        if res is not None:
-            pytest.fail(f"concurrent lookup failed\n{res}")
+    @staticmethod
+    def post_on(conn, path, data):
+        conn.request("POST", path, body=data)
+        resp = conn.getresponse()
+        resp.read()
+        return resp
+
+    def test_create_and_verify(self, post, example_config, example_gencreds):
+        addr, password = example_gencreds()
+        assert post("/create", f"{addr}\t{password}".encode()) == 200
+        assert stored_hash(example_config, addr).startswith("{SHA512-CRYPT}")
+
+        # second login with the same password verifies, a wrong one is refused
+        assert post("/create", f"{addr}\t{password}".encode()) == 200
+        assert post("/create", f"{addr}\twrong{password}".encode()) == 403
+
+    def test_password_special_chars_survive_transport(self, post, example_gencreds):
+        addr, _ = example_gencreds()
+        password = "laksjdlaksjdlak\\sjdlk\"12j'3l1/k2\tj3123"
+        body = f"{addr}\t{password}".encode()
+        assert post("/create", body) == 200
+        assert post("/create", body) == 200
+        assert post("/create", f"{addr}\totherpassword1".encode()) == 403
+
+    def test_password_must_be_utf8(self, post, example_gencreds):
+        addr, _ = example_gencreds()
+        assert post("/create", f"{addr}\tpässwort12".encode()) == 200
+        assert post("/create", addr.encode() + b"\tp\xe4sswort12") == 400
+
+    def test_nul_is_refused_before_crypt_sees_it(self, post, example_gencreds):
+        addr, _ = example_gencreds()
+        assert post("/create", f"{addr}\tpass\0word12".encode()) == 400
+        assert (
+            post("/create", "us\0er12345@chat.example.org\tlongenough1".encode()) == 400
+        )
+
+    def test_refused_creation(self, post, example_gencreds):
+        addr, _ = example_gencreds()
+        assert post("/create", f"{addr}\tshort".encode()) == 403
+        assert post("/create", b"not-an-address\tlongenoughpassword") == 403
+        body = "bürger123@chat.example.org\tlongenoughpw".encode()
+        assert post("/create", body) == 403
+        assert post("/create", b"") == 403
+
+    def test_body_length_limit(self, post, example_gencreds):
+        addr, _ = example_gencreds()
+        fill = CreateHandler.max_body_len - len(addr) - len("\t")
+        body = f"{addr}\t{'x' * fill}".encode()
+        assert len(body) == CreateHandler.max_body_len
+        assert post("/create", body) == 200
+
+        body = f"{addr}\t{'x' * (fill + 1)}".encode()
+        assert len(body) == CreateHandler.max_body_len + 1
+        assert post("/create", body) == 400
+
+    def test_connection_is_reused_across_200_replies(
+        self, connection, example_gencreds
+    ):
+        addr, password = example_gencreds()
+        body = f"{addr}\t{password}".encode()
+        # create, then verify the same password, on one connection
+        for _ in range(2):
+            resp = self.post_on(connection, "/create", body)
+            assert (resp.status, resp.will_close) == (200, False)
+
+    @pytest.mark.parametrize(
+        "path,data,status",
+        [
+            ("/other", b"not read", 404),
+            ("/create", b"x" * (CreateHandler.max_body_len + 1), 400),
+            ("/create", b"not-an-address\tlongenoughpassword", 403),
+        ],
+    )
+    def test_error_replies_close_the_connection(self, connection, path, data, status):
+        resp = self.post_on(connection, path, data)
+        assert (resp.status, resp.will_close) == (status, True)
+
+    @pytest.mark.parametrize("content_length", [None, "-1", "notanumber", "999999"])
+    def test_bad_content_length(self, connection, content_length):
+        # the fixture timeout turns a server that waits for the body into a failure
+        connection.putrequest("POST", "/create", skip_accept_encoding=True)
+        if content_length is not None:
+            connection.putheader("Content-Length", content_length)
+        connection.endheaders()
+        resp = connection.getresponse()
+        assert resp.status == 400
+        assert resp.will_close

chatmaild/src/chatmaild/tests/test_expire.py

@@ -1,14 +1,15 @@
 import itertools
 import os
 import random
+import shutil
 import time
-from datetime import datetime
 from fnmatch import fnmatch
 from pathlib import Path
 
 import pytest
 
 from chatmaild.expire import (
+    Expiry,
     FileEntry,
     MailboxStat,
     expire_to_target,
@@ -39,7 +40,7 @@ def fill_mbox(folderdir):
 
 
 def create_new_messages(basedir, relpaths, size=1000, days=0):
-    now = datetime.utcnow().timestamp()
+    now = time.time()
 
     for relpath in relpaths:
         msg_path = Path(basedir).joinpath(relpath)
@@ -104,6 +105,30 @@ def test_stats_mailbox(mbox1):
     assert mbox3.last_login is None
 
 
+def test_mbox_without_password(mbox1, example_config, capsys):
+    password = Path(mbox1.basedir).joinpath("password")
+    os.remove(password)
+    mbox_rescan = MailboxStat(mbox1.basedir)
+    assert mbox_rescan.last_login is None
+
+    exp = Expiry(example_config, dry=False, now=time.time(), verbose=False)
+    exp.process_mailbox_stat(mbox_rescan)
+    out, err = capsys.readouterr()
+    assert "doesn't have last_login but isn't empty" in err
+    assert os.path.isdir(mbox_rescan.basedir)
+
+    for entry in os.scandir(mbox_rescan.basedir):
+        if os.path.isdir(entry):
+            shutil.rmtree(entry)
+        else:
+            os.remove(entry)
+
+    exp.process_mailbox_stat(mbox_rescan)
+    out, err = capsys.readouterr()
+    assert "doesn't have last_login but isn't empty" not in err
+    assert not os.path.isdir(mbox_rescan.basedir)
+
+
 def test_report_no_mailboxes(example_config):
     args = (str(example_config._inipath),)
     report_main(args)
@@ -124,7 +149,7 @@ def test_report_mdir_filters_by_path(mbox1, example_config):
     """Test that Report with mdir='cur' only counts messages in cur/ subdirectory."""
     from chatmaild.fsreport import Report
 
-    now = datetime.utcnow().timestamp()
+    now = time.time()
 
     # Set password mtime to old enough so min_login_age check passes
     password = Path(mbox1.basedir).joinpath("password")

chatmaild/src/chatmaild/tests/test_lastlogin.py

@@ -1,6 +1,6 @@
 import time
 
-from chatmaild.doveauth import AuthDictProxy
+from chatmaild.doveauth import DoveAuth
 from chatmaild.lastlogin import (
     LastLoginDictProxy,
 )
@@ -9,8 +9,8 @@ from chatmaild.lastlogin import (
 def test_handle_dovecot_request_last_login(testaddr, example_config):
     dictproxy = LastLoginDictProxy(config=example_config)
 
-    authproxy = AuthDictProxy(config=example_config)
-    authproxy.lookup_passdb(testaddr, "1l2k3j1l2k3jl123")
+    doveauth = DoveAuth(example_config)
+    doveauth.create_user(testaddr, "1l2k3j1l2k3jl123")
 
     dictproxy_transactions = {}
 

chatmaild/src/chatmaild/tests/test_metadata.py

@@ -1,4 +1,5 @@
 import io
+import json
 import time
 
 import pytest
@@ -7,6 +8,7 @@ import requests
 from chatmaild.metadata import (
     Metadata,
     MetadataDictProxy,
+    read_appversions,
 )
 from chatmaild.notifier import (
     Notifier,
@@ -324,7 +326,7 @@ def test_turn_credentials_exception_returns_N(notifier, metadata, monkeypatch):
         turn_hostname="turn.example.org",
     )
 
-    def mock_turn_credentials():
+    def mock_turn_credentials(turn_socket_path):
         raise ConnectionRefusedError("socket not available")
 
     monkeypatch.setattr(chatmaild.metadata, "turn_credentials", mock_turn_credentials)
@@ -348,7 +350,9 @@ def test_turn_credentials_success(notifier, metadata, monkeypatch):
         turn_hostname="turn.example.org",
     )
 
-    monkeypatch.setattr(chatmaild.metadata, "turn_credentials", lambda: "user:pass")
+    monkeypatch.setattr(
+        chatmaild.metadata, "turn_credentials", lambda path: "user:pass"
+    )
 
     transactions = {}
     res = dictproxy.handle_dovecot_request(
@@ -360,20 +364,39 @@ def test_turn_credentials_success(notifier, metadata, monkeypatch):
 
 
 def test_iroh_relay(dictproxy):
-    rfile = io.BytesIO(
-        b"\n".join(
-            [
-                b"H",
-                b"Lshared/0123/vendor/vendor.dovecot/pvt/server/vendor/deltachat/irohrelay\tuser@example.org",
-            ]
-        )
-    )
-    wfile = io.BytesIO()
+    key = b"Lshared/0123/vendor/vendor.dovecot/pvt/server/vendor/deltachat/irohrelay\tuser@example.org"
+    rfile, wfile = io.BytesIO(b"H\n" + key), io.BytesIO()
     dictproxy.iroh_relay = "https://example.org/"
     dictproxy.loop_forever(rfile, wfile)
     assert wfile.getvalue() == b"Ohttps://example.org/\n"
 
 
+def test_read_appversions(tmp_path):
+    path = tmp_path.joinpath("appversions.json")
+    assert read_appversions(path) is None
+
+    path.write_text('{\n  "clients": []\n}')
+    assert read_appversions(path) == '{"clients":[]}'
+
+    # the value travels as a single dict protocol line
+    path.write_text('{"clients": [{"clientId": "one\\ntwo"}]}')
+    assert read_appversions(path) == '{"clients":[{"clientId":"one\\ntwo"}]}'
+
+    path.write_text("bad json")
+    assert read_appversions(path) is None
+
+
+def test_appversions_lookup(dictproxy):
+    # the version information shipped with chatmaild is served as a single line
+    key = b"Lshared/0123/vendor/vendor.dovecot/pvt/server/vendor/deltachat/appversions"
+    key += b"\tuser@example.org"
+    rfile, wfile = io.BytesIO(b"H\n" + key), io.BytesIO()
+    dictproxy.loop_forever(rfile, wfile)
+    value = wfile.getvalue()
+    assert value.startswith(b"O") and value.endswith(b"\n")
+    assert json.loads(value[1:])["clients"]
+
+
 def test_legacy_token_migration(metadata, testaddr):
     with metadata.get_metadata_dict(testaddr).modify() as data:
         data[metadata.DEVICETOKEN_KEY] = ["oldtoken1", "oldtoken2"]
@@ -383,3 +406,23 @@ def test_legacy_token_migration(metadata, testaddr):
     tokens = mdict[metadata.DEVICETOKEN_KEY]
     assert isinstance(tokens, dict)
     assert "oldtoken1" in tokens and "oldtoken2" in tokens
+
+
+@pytest.mark.parametrize(
+    "suffix, expected",
+    [
+        (b"vendor/deltachat/maxsmtprecipients", b"O1000\n"),
+        (b"wrong/prefix/key", b"N\n"),
+        (b"vendor/deltachat/unknown", b"N\n"),
+    ],
+    ids=["maxsmtprecipients", "prefix_mismatch", "unknown_name"],
+)
+def test_shared_lookup(dictproxy, suffix, expected):
+    key = (
+        b"Lshared/0123/vendor/vendor.dovecot/pvt/server/"
+        + suffix
+        + b"\tuser@example.org"
+    )
+    rfile, wfile = io.BytesIO(b"H\n" + key), io.BytesIO()
+    dictproxy.loop_forever(rfile, wfile)
+    assert wfile.getvalue() == expected

chatmaild/src/chatmaild/tests/test_migrate_db.py

@@ -63,7 +63,7 @@ def test_migration(tmp_path, example_config, caplog):
         user = example_config.get_user(path.name)
         if last_login:
             assert user.get_last_login_timestamp() == last_login
-        assert password == user.get_userdb_dict()["password"]
+        assert password == user.get_password_hash()
 
     assert not all
     assert not example_config.passdb_path.exists()

chatmaild/src/chatmaild/tests/test_newmail.py

@@ -19,25 +19,36 @@ def test_create_newemail_dict(example_config):
     assert ac1["password"] != ac2["password"]
 
 
-def test_create_newemail_dict_ip(make_config):
-    config = make_config("1.2.3.4")
-    ac = create_newemail_dict(config)
-    assert ac["email"].endswith("@[1.2.3.4]")
+def test_create_newemail_dict_ip(ipv4_config):
+    ac = create_newemail_dict(ipv4_config)
+    assert ac["email"].endswith("@[1.3.3.7]")
 
 
-def test_create_dclogin_url():
-    url = create_dclogin_url("user@example.org", "p@ss w+rd")
+def test_create_dclogin_url(example_config):
+    addr = "user@example.org"
+    password = "p@ss w+rd"
+    url = create_dclogin_url(example_config, addr, password)
     assert url.startswith("dclogin:")
     assert "v=1" in url
     assert "ic=3" in url
 
-    assert "user@example.org" in url
+    assert addr in url
     # password special chars must be encoded
     assert "p%40ss" in url
     assert "w%2Brd" in url
 
 
-def test_print_new_account(capsys, monkeypatch, maildomain, tmpdir, example_config):
+def test_create_dclogin_url_ipv4(ipv4_config):
+    addr = "user@[1.3.3.7]"
+    password = "p@ss w+rd"
+    url = create_dclogin_url(ipv4_config, addr, password)
+    assert url.startswith("dclogin:")
+    assert "v=1" in url
+    assert "ic=3" in url
+    assert addr in url
+
+
+def test_print_new_account(capsys, monkeypatch, tmpdir, example_config):
     monkeypatch.setattr(chatmaild.newemail, "CONFIG_PATH", str(example_config._inipath))
     print_new_account()
     out, err = capsys.readouterr()

chatmaild/src/chatmaild/tests/test_syslimits.py

@@ -0,0 +1,45 @@
+import shutil
+
+import psutil
+
+from chatmaild.syslimits import has_sufficient_resources
+
+PERMISSIVE = {
+    "max_load_1m": "99999",
+    "min_available_memory": "0",
+    "min_free_disk_space": "0",
+}
+
+
+def test_rejects_constrained_system(make_config, caplog):
+    assert has_sufficient_resources(make_config("chat.example.org", PERMISSIVE))
+    for settings in (
+        {"max_load_1m": "-1.0"},
+        {"min_available_memory": "99999999G"},
+        {"min_free_disk_space": "99999999G"},
+    ):
+        config = make_config("chat.example.org", PERMISSIVE | settings)
+        caplog.clear()
+        assert not has_sufficient_resources(config), settings
+        assert "registration rejected" in caplog.text
+
+
+def test_unreadable_disk_does_not_reject(make_config, caplog):
+    config = make_config(
+        "chat.example.org", PERMISSIVE | {"min_free_disk_space": "99999999G"}
+    )
+    shutil.rmtree(config.mailboxes_dir)
+    assert has_sufficient_resources(config)
+    assert "ignoring" in caplog.text
+
+
+def test_one_unreadable_value_keeps_other_checks(make_config, monkeypatch, caplog):
+    def raise_error(*args):
+        raise psutil.Error("dud")
+
+    monkeypatch.setattr(psutil, "getloadavg", raise_error)
+    config = make_config(
+        "chat.example.org", PERMISSIVE | {"min_free_disk_space": "99999999G"}
+    )
+    assert not has_sufficient_resources(config)
+    assert "ignoring" in caplog.text

chatmaild/src/chatmaild/tests/test_turn.py

@@ -0,0 +1,46 @@
+import socket
+import threading
+
+import pytest
+
+from chatmaild.metadata import turn_credentials
+
+
+@pytest.fixture
+def turn_socket(tmp_path):
+    sock_path = str(tmp_path / "turn.socket")
+    server = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    server.bind(sock_path)
+    server.listen(1)
+    yield sock_path, server
+    server.close()
+
+
+def test_turn_credentials_timeout(turn_socket):
+    sock_path, server = turn_socket
+    with pytest.raises(socket.timeout):
+        # Inside turn_credentials the kernel listen backlog (1)
+        # completes connect() without accept()
+        # so the client blocks on readline() until the 5s timeout fires.
+        turn_credentials(sock_path)
+
+
+def test_turn_credentials_connection_refused_on_not_existing_socket(tmp_path):
+    missing = str(tmp_path / "nonexistent.socket")
+    with pytest.raises((ConnectionRefusedError, FileNotFoundError)):
+        turn_credentials(missing)
+
+
+def test_turn_credentials_socket_success(turn_socket):
+    sock_path, server = turn_socket
+
+    def respond():
+        conn, _ = server.accept()
+        conn.sendall(b"testuser:testpass\n")
+        conn.close()
+
+    t = threading.Thread(target=respond, daemon=True)
+    t.start()
+
+    result = turn_credentials(sock_path)
+    assert result == "testuser:testpass"

chatmaild/src/chatmaild/tests/test_turnserver.py

@@ -1,73 +0,0 @@
-import socket
-import threading
-import time
-from unittest.mock import patch
-
-import pytest
-
-from chatmaild.turnserver import turn_credentials
-
-SOCKET_PATH = "/run/chatmail-turn/turn.socket"
-
-
-@pytest.fixture
-def turn_socket(tmp_path):
-    """Create a real Unix socket server at a temp path."""
-    sock_path = str(tmp_path / "turn.socket")
-    server = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
-    server.bind(sock_path)
-    server.listen(1)
-    yield sock_path, server
-    server.close()
-
-
-def _call_turn_credentials(sock_path):
-    """Call turn_credentials but connect to sock_path instead of hardcoded path."""
-    original_connect = socket.socket.connect
-
-    def patched_connect(self, address):
-        if address == SOCKET_PATH:
-            address = sock_path
-        return original_connect(self, address)
-
-    with patch.object(socket.socket, "connect", patched_connect):
-        return turn_credentials()
-
-
-def test_turn_credentials_timeout(turn_socket):
-    """Server accepts but never responds — must raise socket.timeout."""
-    sock_path, server = turn_socket
-
-    def accept_and_hang():
-        conn, _ = server.accept()
-        time.sleep(30)
-        conn.close()
-
-    t = threading.Thread(target=accept_and_hang, daemon=True)
-    t.start()
-
-    with pytest.raises(socket.timeout):
-        _call_turn_credentials(sock_path)
-
-
-def test_turn_credentials_connection_refused(tmp_path):
-    """Socket file doesn't exist — must raise ConnectionRefusedError or FileNotFoundError."""
-    missing = str(tmp_path / "nonexistent.socket")
-    with pytest.raises((ConnectionRefusedError, FileNotFoundError)):
-        _call_turn_credentials(missing)
-
-
-def test_turn_credentials_success(turn_socket):
-    """Server responds with credentials — must return stripped string."""
-    sock_path, server = turn_socket
-
-    def respond():
-        conn, _ = server.accept()
-        conn.sendall(b"testuser:testpass\n")
-        conn.close()
-
-    t = threading.Thread(target=respond, daemon=True)
-    t.start()
-
-    result = _call_turn_credentials(sock_path)
-    assert result == "testuser:testpass"

chatmaild/src/chatmaild/tests/test_user.py

@@ -8,28 +8,23 @@ def test_login_timestamp(testaddr, example_config):
     assert user.get_last_login_timestamp() == 86400 * 2
 
 
-def test_get_user_dict_not_set(testaddr, example_config, caplog):
+def test_get_password_hash_not_set(testaddr, example_config, caplog):
     user = example_config.get_user(testaddr)
     assert not caplog.records
-    assert user.get_userdb_dict() == {}
+    assert user.get_password_hash() is None
     assert len(caplog.records) == 0
 
     user.set_password("")
-    assert user.get_userdb_dict() == {}
+    assert user.get_password_hash() is None
     assert len(caplog.records) == 1
 
 
-def test_get_user_dict(make_config, tmp_path):
+def test_get_password_hash(make_config, tmp_path):
     config = make_config("something.testrun.org")
-    addr = "user1@something.org"
-    user = config.get_user(addr)
+    user = config.get_user("user1@something.org")
     enc_password = "l1k2j31lk2j3l1k23j123"
     user.set_password(enc_password)
-    data = user.get_userdb_dict()
-    assert addr in str(data["home"])
-    assert data["uid"] == "vmail"
-    assert data["gid"] == "vmail"
-    assert data["password"] == enc_password
+    assert user.get_password_hash() == enc_password
 
 
 def test_no_mailboxes_dir(testaddr, example_config, tmp_path):

chatmaild/src/chatmaild/turnserver.py

@@ -1,10 +0,0 @@
-#!/usr/bin/env python3
-import socket
-
-
-def turn_credentials() -> str:
-    with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as client_socket:
-        client_socket.settimeout(5)
-        client_socket.connect("/run/chatmail-turn/turn.socket")
-        with client_socket.makefile("rb") as file:
-            return file.readline().decode("utf-8").strip()

chatmaild/src/chatmaild/user.py

@@ -21,20 +21,17 @@ class User:
     def can_track(self):
         return "@" in self.addr
 
-    def get_userdb_dict(self):
-        """Return a non-empty dovecot 'userdb' style dict
-        if the user has an existing non-empty password"""
+    def get_password_hash(self):
         try:
-            pw = self.password_path.read_text()
+            passhash = self.password_path.read_text()
         except FileNotFoundError:
-            return {}
+            return None
 
-        if not pw:
+        if not passhash:
             logging.error(f"password is empty for: {self.addr}")
-            return {}
+            return None
 
-        home = str(self.maildir)
-        return dict(addr=self.addr, home=home, uid=self.uid, gid=self.gid, password=pw)
+        return passhash
 
     def is_incoming_cleartext_ok(self):
         return not self.enforce_E2EE_path.exists()

cmdeploy/pyproject.toml

@@ -19,6 +19,8 @@ dependencies = [
   "pytest-xdist", 
   "execnet",
   "imap_tools",
+  "jinja2",
+  "lupa",
   "deltachat-rpc-client",
   "deltachat-rpc-server",
 ]
@@ -26,10 +28,6 @@ dependencies = [
 [project.scripts]
 cmdeploy = "cmdeploy.cmdeploy:main"
 
-[project.entry-points.pytest11]
-"chatmaild.testplugin" = "chatmaild.tests.plugin"
-"cmdeploy.testplugin" = "cmdeploy.tests.plugin"
-
 [tool.pytest.ini_options]
 addopts = "-v -ra --strict-markers"
 

cmdeploy/src/cmdeploy/__init__.py

@@ -0,0 +1 @@
+

cmdeploy/src/cmdeploy/acmetool/__init__.py

@@ -4,6 +4,8 @@ from ..basedeploy import Deployer
 
 
 class AcmetoolDeployer(Deployer):
+    bin_path = "/usr/bin/acmetool"
+
     def __init__(self, email, domains):
         self.domains = domains
         self.email = email
@@ -41,8 +43,12 @@ class AcmetoolDeployer(Deployer):
             domains=self.domains,
         )
 
-        self.ensure_systemd_unit("acmetool/acmetool-redirector.service")
-        self.ensure_systemd_unit("acmetool/acmetool-reconcile.service")
+        self.ensure_systemd_unit(
+            "acmetool/acmetool-redirector.service.j2", bin_path=self.bin_path
+        )
+        self.ensure_systemd_unit(
+            "acmetool/acmetool-reconcile.service.j2", bin_path=self.bin_path
+        )
         self.ensure_systemd_unit("acmetool/acmetool-reconcile.timer")
 
     def activate(self):
@@ -52,5 +58,5 @@ class AcmetoolDeployer(Deployer):
 
         server.shell(
             name=f"Reconcile certificates for: {', '.join(self.domains)}",
-            commands=["acmetool --batch --xlog.severity=debug reconcile"],
+            commands=[f"{self.bin_path} --batch --xlog.severity=debug reconcile"],
         )

cmdeploy/src/cmdeploy/acmetool/acmetool-reconcile.service.j2

@@ -4,5 +4,5 @@ After=network.target
 
 [Service]
 Type=oneshot
-ExecStart=/usr/bin/acmetool --batch reconcile
+ExecStart={{ bin_path }} --batch reconcile
 

cmdeploy/src/cmdeploy/acmetool/acmetool-redirector.service.j2

@@ -3,7 +3,7 @@ Description=acmetool HTTP redirector
 
 [Service]
 Type=notify
-ExecStart=/usr/bin/acmetool redirector --service.uid=daemon --bind=127.0.0.1:402
+ExecStart={{ bin_path }} redirector --service.uid=daemon --bind=127.0.0.1:402
 Restart=always
 RestartSec=30
 

cmdeploy/src/cmdeploy/acmetool/response-file.yaml.j2

@@ -1,2 +1,2 @@
 "acme-enter-email": "{{ email }}"
-"acme-agreement:https://letsencrypt.org/documents/LE-SA-v1.6-August-18-2025.pdf": true
+"acme-agreement:https://letsencrypt.org/documents/LE-SA-v1.8-July-06-2026.pdf": true

cmdeploy/src/cmdeploy/basedeploy.py

@@ -51,7 +51,7 @@ def get_resource(arg, pkg=__package__):
     return importlib.resources.files(pkg).joinpath(arg)
 
 
-def configure_remote_units(deployer, mail_domain, units) -> None:
+def configure_remote_units(deployer, mail_domain, units, **kwargs) -> None:
     remote_base_dir = "/usr/local/lib/chatmaild"
     remote_venv_dir = f"{remote_base_dir}/venv"
     remote_chatmail_inipath = f"{remote_base_dir}/chatmail.ini"
@@ -63,6 +63,7 @@ def configure_remote_units(deployer, mail_domain, units) -> None:
             config_path=remote_chatmail_inipath,
             remote_venv_dir=remote_venv_dir,
             mail_domain=mail_domain,
+            **kwargs,
         )
 
         basename = fn if "." in fn else f"{fn}.service"
@@ -166,7 +167,7 @@ class Deployer:
             return self.put_template(src, dest, **kwargs)
         return self.put_file(src, dest)
 
-    def put_file(self, src, dest, mode="644"):
+    def put_file(self, src, dest, mode="644", **kwargs):
         if isinstance(src, str):
             src = get_resource(src)
         res = files.put(
@@ -176,6 +177,7 @@ class Deployer:
             user="root",
             group="root",
             mode=mode,
+            **kwargs,
         )
 
         return self._update_restart_signals(dest, res)
@@ -225,7 +227,7 @@ class Deployer:
         res = files.directory(name=name, path=path, present=False, **kwargs)
         return self._update_restart_signals(path, res)
 
-    def download_executable(self, url, dest, sha256sum, extract=None):
+    def download_executable(self, url, dest, sha256sum, extract=None, mode="755"):
         existing = host.get_fact(Sha256File, dest)
         if existing == sha256sum:
             return
@@ -242,7 +244,7 @@ class Deployer:
                 f"({dl_cmd}"
                 f" && echo '{sha256sum}  {tmp}' | sha256sum -c"
                 f" && mv {tmp} {dest})",
-                f"chmod 755 {dest}",
+                f"chmod {mode} {dest}",
             ],
         )
         self.need_restart = True

cmdeploy/src/cmdeploy/cmdeploy.py

@@ -84,13 +84,24 @@ def run_cmd_options(parser):
     add_ssh_host_option(parser)
 
 
+def _warn_unused_settings(unused_keys, out):
+    if unused_keys:
+        names = ", ".join(unused_keys)
+        out.red(
+            f"WARNING: chatmail.ini contains settings that have no effect: {names}\n"
+            "Please remove them from chatmail.ini."
+        )
+
+
 def run_cmd(args, out):
     """Deploy chatmail services on the remote server."""
 
-    ssh_host = args.ssh_host if args.ssh_host else args.config.mail_domain
+    ssh_host = args.ssh_host if args.ssh_host else args.config.mail_domain_bare
     sshexec = get_sshexec(ssh_host)
     require_iroh = args.config.enable_iroh_relay
     strict_tls = args.config.tls_cert_mode == "acme"
+    if args.config.ipv4_relay:
+        args.dns_check_disabled = True
     if not args.dns_check_disabled:
         remote_data = dns.get_initial_remote_data(sshexec, args.config.mail_domain)
         if not dns.check_initial_remote_data(remote_data, strict_tls=strict_tls, print=out.red):
@@ -119,8 +130,11 @@ def run_cmd(args, out):
         elif not args.dns_check_disabled and strict_tls and not remote_data["acme_account_url"]:
             out.red("Deploy completed but letsencrypt not configured")
             out.red("Run 'cmdeploy run' again")
+        elif args.config.ipv4_relay:
+            out.green("Deploy completed.")
         else:
             out.green("Deploy completed, call `cmdeploy dns` next.")
+        _warn_unused_settings(args.config._unused_keys, out)
         return 0
     except subprocess.CalledProcessError:
         out.red("Deploy failed")
@@ -140,6 +154,10 @@ def dns_cmd_options(parser):
 
 def dns_cmd(args, out):
     """Check DNS entries and optionally generate dns zone file."""
+    if args.config.ipv4_relay:
+        ipv4 = args.config.ipv4_relay
+        print(f"[WARNING] {ipv4} is not a domain, skipping DNS checks.")
+        return 0
     ssh_host = args.ssh_host if args.ssh_host else args.config.mail_domain
     sshexec = get_sshexec(ssh_host, verbose=args.verbose)
     tls_cert_mode = args.config.tls_cert_mode
@@ -177,7 +195,7 @@ def status_cmd_options(parser):
 def status_cmd(args, out):
     """Display status for online chatmail instance."""
 
-    ssh_host = args.ssh_host if args.ssh_host else args.config.mail_domain
+    ssh_host = args.ssh_host if args.ssh_host else args.config.mail_domain_bare
     sshexec = get_sshexec(ssh_host, verbose=args.verbose)
 
     out.green(f"chatmail domain: {args.config.mail_domain}")

cmdeploy/src/cmdeploy/deployers.py

@@ -33,6 +33,7 @@ from .filtermail.deployer import FiltermailDeployer
 from .mtail.deployer import MtailDeployer
 from .nginx.deployer import NginxDeployer
 from .opendkim.deployer import OpendkimDeployer
+from .pins import IROH_ARTIFACTS, TURN_ARTIFACTS
 from .postfix.deployer import PostfixDeployer
 from .selfsigned.deployer import SelfSignedTlsDeployer
 from .www import build_webpages, find_merge_conflict, get_paths
@@ -98,6 +99,23 @@ def _install_remote_venv_with_chatmaild(deployer) -> None:
         dest=remote_dist_file,
     )
 
+    # Remove venv if its Python major.minor doesn't match the system Python
+    server.shell(
+        name="remove stale chatmaild venv if python version changed",
+        commands=[
+            "\n".join(
+                [
+                    r"re='[0-9]+\.[0-9]+'",  # major.minor out of 'Python X.Y.Z'
+                    'sys_version=$(python3 --version 2>/dev/null | grep -oE "$re")',
+                    f'venv_version=$({remote_venv_dir}/bin/python --version 2>/dev/null | grep -oE "$re")',
+                    # an empty sys_version means we could not tell: keep the venv
+                    f'[ -z "$sys_version" ] || [ "$sys_version" = "$venv_version" ] '
+                    f"|| rm -rf {remote_venv_dir}",
+                ]
+            )
+        ],
+    )
+
     pip.virtualenv(
         name=f"chatmaild virtualenv {remote_venv_dir}",
         path=remote_venv_dir,
@@ -138,9 +156,22 @@ class UnboundDeployer(Deployer):
         # On an IPv4-only system, if unbound is started but not configured,
         # it causes subsequent steps to fail to resolve hosts.
         with blocked_service_startup():
+            # dns-root-data is an optional package
+            # that contains /usr/share/dns/root.key
+            #
+            # This file is copied into /var/lib/unbound/root.key
+            # at the start of "unbound" systemd unit
+            # by /usr/libexec/unbound-helper shell script
+            # from the "unbound" package as of version 1.17.1-2+deb12u4
+            #
+            # The same /var/lib/unbound/root.key can be retrieved directly
+            # following the procedure from
+            # <https://www.rfc-editor.org/info/rfc7958/#section-3.1>
+            # with "unbound-anchor -a /var/lib/unbound/root.key"
+            # We don't install and use "unbound-anchor".
             apt.packages(
                 name="Install unbound",
-                packages=["unbound", "unbound-anchor", "dnsutils"],
+                packages=["unbound", "dns-root-data", "dnsutils"],
             )
 
     def configure(self):
@@ -164,23 +195,16 @@ class UnboundDeployer(Deployer):
         self.put_file(
             src=BytesIO(b"nameserver 127.0.0.1\nnameserver 9.9.9.9\n"),
             dest="/etc/resolv.conf",
+            force=True,
         )
-        server.shell(
-            name="Generate root keys for validating DNSSEC",
-            commands=[
-                "unbound-anchor -a /var/lib/unbound/root.key || true",
-            ],
+        self.ensure_directory(
+            path="/etc/unbound/unbound.conf.d",
+        )
+        self.put_template(
+            "unbound/unbound.conf.j2",
+            "/etc/unbound/unbound.conf.d/chatmail.conf",
+            disable_ipv6=self.config.disable_ipv6,
         )
-        if self.config.disable_ipv6:
-            self.ensure_directory(
-                path="/etc/unbound/unbound.conf.d",
-            )
-            self.put_template(
-                "unbound/unbound.conf.j2",
-                "/etc/unbound/unbound.conf.d/chatmail.conf",
-            )
-        else:
-            self.remove_file("/etc/unbound/unbound.conf.d/chatmail.conf")
 
     def activate(self):
         server.shell(
@@ -247,6 +271,13 @@ class LegacyRemoveDeployer(Deployer):
     def install(self):
         apt.packages(name="Remove rspamd", packages="rspamd", present=False)
 
+        # unbound-anchor was used to download /var/lib/unbound/root.key
+        # It is replaced by dns-root-data which contains /usr/share/dns/root.key.
+        # unbound systemd unit copies /usr/share/dns/root.key
+        # into /var/lib/unbound/root.key automatically on start
+        # as long as /usr/share/dns/root.key is present.
+        apt.packages(name="Remove unbound-anchor", packages="unbound-anchor", present=False)
+
         # remove historic expunge script
         # which is now implemented through a systemd timer (chatmail-expire)
         self.remove_file("/etc/cron.d/expunge")
@@ -288,55 +319,48 @@ def check_config(config):
 
 
 class TurnDeployer(Deployer):
+    bin_path = "/usr/local/bin/chatmail-turn"
+
     def __init__(self, mail_domain):
         self.mail_domain = mail_domain
         self.units = ["turnserver"]
 
     def install(self):
-        (url, sha256sum) = {
-            "x86_64": (
-                "https://github.com/chatmail/chatmail-turn/releases/download/v0.4/chatmail-turn-x86_64-linux",
-                "1ec1f5c50122165e858a5a91bcba9037a28aa8cb8b64b8db570aa457c6141a8a",
-            ),
-            "aarch64": (
-                "https://github.com/chatmail/chatmail-turn/releases/download/v0.4/chatmail-turn-aarch64-linux",
-                "0fb3e792419494e21ecad536464929dba706bb2c88884ed8f1788141d26fc756",
-            ),
-        }[host.get_fact(facts.server.Arch)]
-        self.download_executable(url, "/usr/local/bin/chatmail-turn", sha256sum)
+        (url, sha256sum) = TURN_ARTIFACTS[host.get_fact(facts.server.Arch)]
+        self.download_executable(url, self.bin_path, sha256sum)
 
     def configure(self):
-        configure_remote_units(self, self.mail_domain, self.units)
+        configure_remote_units(
+            self, self.mail_domain, self.units, bin_path=self.bin_path
+        )
 
     def activate(self):
         activate_remote_units(self, self.units)
 
 
 class IrohDeployer(Deployer):
+    bin_path = "/usr/local/bin/iroh-relay"
+    config_path = "/etc/iroh-relay.toml"
+
     def __init__(self, enable_iroh_relay):
         self.enable_iroh_relay = enable_iroh_relay
 
     def install(self):
-        (url, sha256sum) = {
-            "x86_64": (
-                "https://github.com/n0-computer/iroh/releases/download/v0.35.0/iroh-relay-v0.35.0-x86_64-unknown-linux-musl.tar.gz",
-                "45c81199dbd70f8c4c30fef7f3b9727ca6e3cea8f2831333eeaf8aa71bf0fac1",
-            ),
-            "aarch64": (
-                "https://github.com/n0-computer/iroh/releases/download/v0.35.0/iroh-relay-v0.35.0-aarch64-unknown-linux-musl.tar.gz",
-                "f8ef27631fac213b3ef668d02acd5b3e215292746a3fc71d90c63115446008b1",
-            ),
-        }[host.get_fact(facts.server.Arch)]
+        (url, sha256sum) = IROH_ARTIFACTS[host.get_fact(facts.server.Arch)]
         self.download_executable(
             url,
-            "/usr/local/bin/iroh-relay",
+            self.bin_path,
             sha256sum,
             extract="gunzip | tar -xf - ./iroh-relay -O",
         )
 
     def configure(self):
-        self.ensure_systemd_unit("iroh-relay.service")
-        self.put_file("iroh-relay.toml", "/etc/iroh-relay.toml")
+        self.ensure_systemd_unit(
+            "iroh-relay.service.j2",
+            bin_path=self.bin_path,
+            config_path=self.config_path,
+        )
+        self.put_file("iroh-relay.toml", self.config_path)
 
     def activate(self):
         self.ensure_service(
@@ -357,6 +381,8 @@ class ChatmailVenvDeployer(Deployer):
     def __init__(self, config):
         self.config = config
         self.units = (
+            # doveauth must restart when chatmaild/ini file changes
+            "doveauth",
             "chatmail-metadata",
             "lastlogin",
             "chatmail-expire",
@@ -370,7 +396,7 @@ class ChatmailVenvDeployer(Deployer):
 
     def configure(self):
         _configure_remote_venv_with_chatmaild(self, self.config)
-        configure_remote_units(self, self.config.mail_domain, self.units)
+        configure_remote_units(self, self.config.mail_domain_bare, self.units)
 
     def activate(self):
         activate_remote_units(self, self.units)
@@ -391,6 +417,12 @@ class ChatmailDeployer(Deployer):
             src=BytesIO(b'APT::Install-Recommends "false";\n'),
             dest="/etc/apt/apt.conf.d/00InstallRecommends",
         )
+        # Pin dovecot-* to priority -1 before any apt operation, apt should
+        # never manage dovecot as our version might be lower than the distro's.
+        self.put_file(
+            src=StringIO("Package: dovecot-*\nPin: version *\nPin-Priority: -1\n"),
+            dest="/etc/apt/preferences.d/pin-dovecot",
+        )
         apt.update(name="apt update", cache_time=24 * 3600)
         apt.upgrade(name="upgrade apt packages", auto_remove=True)
 
@@ -469,7 +501,7 @@ def deploy_chatmail(config_path: Path, disable_mail: bool, website_only: bool) -
     """
     config = read_config(config_path)
     check_config(config)
-    mail_domain = config.mail_domain
+    bare_host = config.mail_domain_bare
 
     if website_only:
         Deployment().perform_stages([WebsiteDeployer(config)])
@@ -505,15 +537,17 @@ def deploy_chatmail(config_path: Path, disable_mail: bool, website_only: bool) -
             ("nginx", 443),
             (["master", "smtpd"], 465),
             (["master", "smtpd"], 587),
-            (["imap-login", "dovecot"], 993),
+            (["dovecot", "imap-login"], 993),
             ("iroh-relay", 3340),
             ("mtail", 3903),
-            ("stats", 3904),
+            (["dovecot", "stats"], 3904),
             ("nginx", 8443),
             (["master", "smtpd"], config.postfix_reinject_port),
             (["master", "smtpd"], config.postfix_reinject_port_incoming),
             ("filtermail", config.filtermail_smtp_port),
             ("filtermail", config.filtermail_smtp_port_incoming),
+            ("filtermail", config.filtermail_http_port_incoming),
+            ("filtermail", config.filtermail_lmtp_port_transport),
         ]
         for service, port in port_services:
             print(f"Checking if port {port} is available for {service}...")
@@ -526,7 +560,7 @@ def deploy_chatmail(config_path: Path, disable_mail: bool, website_only: bool) -
                     )
                     exit(1)
 
-    tls_deployer = get_tls_deployer(config, mail_domain)
+    tls_deployer = get_tls_deployer(config, bare_host)
 
     all_deployers = [
         ChatmailDeployer(config),
@@ -534,13 +568,13 @@ def deploy_chatmail(config_path: Path, disable_mail: bool, website_only: bool) -
         FiltermailDeployer(),
         JournaldDeployer(),
         UnboundDeployer(config),
-        TurnDeployer(mail_domain),
+        TurnDeployer(bare_host),
         IrohDeployer(config.enable_iroh_relay),
         tls_deployer,
         WebsiteDeployer(config),
         ChatmailVenvDeployer(config),
         MtastsDeployer(),
-        OpendkimDeployer(mail_domain),
+        *([] if config.ipv4_relay else [OpendkimDeployer(bare_host)]),
         # Dovecot should be started before Postfix
         # because it creates authentication socket
         # required by Postfix.

cmdeploy/src/cmdeploy/dovecot/auth.conf

@@ -1,12 +0,0 @@
-uri = proxy:/run/doveauth/doveauth.socket:auth
-iterate_disable = no
-iterate_prefix = userdb/
-
-default_pass_scheme = plain
-# %E escapes characters " (double quote), ' (single quote) and \ (backslash) with \ (backslash).
-# See <https://doc.dovecot.org/2.3/configuration_manual/config_file/config_variables/#modifiers>
-# for documentation.
-#
-# We escape user-provided input and use double quote as a separator.
-password_key = passdb/%Ew"%Eu
-user_key = userdb/%Eu

cmdeploy/src/cmdeploy/dovecot/auth.lua.j2

@@ -0,0 +1,68 @@
+-- Existing addresses are served from the maildir directly.
+-- Unknown ones are offered to doveauth, which owns the creation policy.
+local mailboxes_dir = "{{ config.mailboxes_dir }}"
+local domain_suffix = "@{{ config.mail_domain }}"
+local create_url = "http://127.0.0.1:{{ config.doveauth_http_port }}/create"
+
+local http_client
+
+local function is_ours(user)
+  return user:sub(-#domain_suffix) == domain_suffix
+     and not user:find("/", 1, true)
+end
+
+local function password_hash(user)
+  local fh = io.open(mailboxes_dir .. "/" .. user .. "/password", "r")
+  if not fh then
+    return nil
+  end
+  local hash, rest = fh:read("l", "a")
+  fh:close()
+  if hash == nil or hash == "" or rest ~= "" then
+    return nil
+  end
+  return hash
+end
+
+local function userdb_fields(user)
+  return {home = mailboxes_dir .. "/" .. user, uid = "vmail", gid = "vmail"}
+end
+
+local function create(user, password)
+  local request = http_client:request({url = create_url, method = "POST"})
+  request:set_payload(user .. "\t" .. password)
+  return request:submit():status()
+end
+
+-- Entry points called by dovecot
+
+function script_init()
+  http_client = dovecot.http.client({request_timeout_msecs = 5000, max_attempts = 1})
+  return 0
+end
+
+function auth_userdb_lookup(req)
+  if not is_ours(req.user) or password_hash(req.user) == nil then
+    return dovecot.auth.USERDB_RESULT_USER_UNKNOWN, {}
+  end
+  return dovecot.auth.USERDB_RESULT_OK, userdb_fields(req.user)
+end
+
+function auth_password_verify(req, password)
+  if not is_ours(req.user) then
+    return dovecot.auth.PASSDB_RESULT_USER_UNKNOWN, {}
+  end
+  local hash = password_hash(req.user)
+  if hash == nil then
+    -- doveauth refuses with 4xx; dovecot reports its own failures as 9000 and up
+    local status = create(req.user, password)
+    if status >= 500 then
+      return dovecot.auth.PASSDB_RESULT_INTERNAL_FAILURE, {}
+    elseif status ~= 200 then
+      return dovecot.auth.PASSDB_RESULT_USER_UNKNOWN, {}
+    end
+  elseif req:password_verify(hash, password) ~= 1 then
+    return dovecot.auth.PASSDB_RESULT_PASSWORD_MISMATCH, {}
+  end
+  return dovecot.auth.PASSDB_RESULT_OK, userdb_fields(req.user)
+end

cmdeploy/src/cmdeploy/dovecot/deployer.py

@@ -1,11 +1,10 @@
-import io
 import urllib.request
 
 from chatmaild.config import Config
 from pyinfra import host
 from pyinfra.facts.deb import DebPackages
 from pyinfra.facts.server import Arch, Command, Sysctl
-from pyinfra.operations import apt, files, server
+from pyinfra.operations import files, server
 
 from cmdeploy.basedeploy import (
     Deployer,
@@ -14,18 +13,15 @@ from cmdeploy.basedeploy import (
     configure_remote_units,
     is_in_container,
 )
+from cmdeploy.pins import DOVECOT_SHA256, DOVECOT_VERSION
 
-DOVECOT_ARCHIVE_VERSION = "2.3.21+dfsg1-3"
-DOVECOT_PACKAGE_VERSION = f"1:{DOVECOT_ARCHIVE_VERSION}"
+VERSION_ID_CMD = "grep '^VERSION_ID=' /etc/os-release"
 
-DOVECOT_SHA256 = {
-    ("core", "amd64"): "dd060706f52a306fa863d874717210b9fe10536c824afe1790eec247ded5b27d",
-    ("core", "arm64"): "e7548e8a82929722e973629ecc40fcfa886894cef3db88f23535149e7f730dc9",
-    ("imapd", "amd64"): "8d8dc6fc00bbb6cdb25d345844f41ce2f1c53f764b79a838eb2a03103eebfa86",
-    ("imapd", "arm64"): "178fa877ddd5df9930e8308b518f4b07df10e759050725f8217a0c1fb3fd707f",
-    ("lmtpd", "amd64"): "2f69ba5e35363de50962d42cccbfe4ed8495265044e244007d7ccddad77513ab",
-    ("lmtpd", "arm64"): "89f52fb36524f5877a177dff4a713ba771fd3f91f22ed0af7238d495e143b38f",
-}
+
+def _stamped_version(deb_release: int) -> str:
+    """Version as built, including the per-distro suffix stamped by
+    chatmail/dovecot CI into package version and filename."""
+    return f"{DOVECOT_VERSION}+deb{deb_release}u1"
 
 
 class DovecotDeployer(Deployer):
@@ -34,41 +30,37 @@ class DovecotDeployer(Deployer):
     def __init__(self, config, disable_mail):
         self.config = config
         self.disable_mail = disable_mail
-        self.units = ["doveauth"]
+        self.units = []
 
     def install(self):
         arch = host.get_fact(Arch)
+        deb_release = _parse_version_id(host.get_fact(Command, VERSION_ID_CMD))
         with blocked_service_startup():
             debs = []
-            for pkg in ("core", "imapd", "lmtpd"):
-                deb, changed = _download_dovecot_package(pkg, arch)
+            for pkg in ("core", "imapd", "lmtpd", "auth-lua"):
+                deb, changed = _download_dovecot_package(pkg, arch, deb_release)
                 self.need_restart |= changed
                 if deb:
                     debs.append(deb)
             if debs:
                 deb_list = " ".join(debs)
-                # First dpkg may fail on missing dependencies (stderr suppressed);
-                # apt-get --fix-broken pulls them in, then dpkg retries cleanly.
+                # apt-get install with local .deb paths resolves depends
+                # against the configured repos (e.g. pulls libwrap0),
+                # The pin file written earlier by ChatmailDeployer prevents apt
+                # from installing a 'wrong' version
                 server.shell(
                     name="Install dovecot packages",
                     commands=[
-                        f"dpkg --force-confdef --force-confold -i {deb_list} 2> /dev/null || true",
-                        "DEBIAN_FRONTEND=noninteractive apt-get -y --fix-broken install",
-                        f"dpkg --force-confdef --force-confold -i {deb_list}",
+                        "DEBIAN_FRONTEND=noninteractive apt-get install -y "
+                        '-o Dpkg::Options::="--force-confdef" '
+                        '-o Dpkg::Options::="--force-confold" '
+                        f"--allow-downgrades {deb_list}",
                     ],
                 )
                 self.need_restart = True
-        self.put_file(
-            src=io.StringIO(
-                "Package: dovecot-*\n"
-                "Pin: version *\n"
-                "Pin-Priority: -1\n"
-            ),
-            dest="/etc/apt/preferences.d/pin-dovecot",
-        )
 
     def configure(self):
-        configure_remote_units(self, self.config.mail_domain, self.units)
+        configure_remote_units(self, self.config.mail_domain_bare, self.units)
         _configure_dovecot(self, self.config)
 
     def activate(self):
@@ -78,7 +70,7 @@ class DovecotDeployer(Deployer):
         if not self.disable_mail and not self.need_restart:
             stale = host.get_fact(
                 Command,
-                'pid=$(systemctl show -p MainPID --value dovecot.service 2>/dev/null);'
+                "pid=$(systemctl show -p MainPID --value dovecot.service 2>/dev/null);"
                 ' [ "${pid:-0}" != "0" ] && readlink "/proc/$pid/exe" 2>/dev/null | grep -q "(deleted)"'
                 " && echo STALE || true",
             )
@@ -93,6 +85,15 @@ class DovecotDeployer(Deployer):
         )
 
 
+def _parse_version_id(version_line: str) -> int:
+    """Debian major release from an /etc/os-release VERSION_ID line."""
+    _, _, raw = (version_line or "").strip().partition("=")
+    try:
+        return int(raw.strip('"'))
+    except ValueError:
+        raise ValueError(f"cannot determine Debian release from {version_line!r}")
+
+
 def _pick_url(primary, fallback):
     try:
         req = urllib.request.Request(primary, method="HEAD")
@@ -102,27 +103,36 @@ def _pick_url(primary, fallback):
         return fallback
 
 
-def _download_dovecot_package(package: str, arch: str) -> tuple[str | None, bool]:
+def _download_dovecot_package(package: str, arch: str, deb_release: int) -> tuple[str | None, bool]:
     """Download a dovecot .deb if needed, return (path, changed)."""
     arch = "amd64" if arch == "x86_64" else arch
     arch = "arm64" if arch == "aarch64" else arch
 
     pkg_name = f"dovecot-{package}"
-    sha256 = DOVECOT_SHA256.get((package, arch))
-    if sha256 is None:
-        op = apt.packages(packages=[pkg_name])
-        return None, bool(getattr(op, "changed", False))
+    try:
+        # never fall back to the distro package: it is pinned to -1 and would
+        # in any case be a version we did not build and do not support
+        sha256 = DOVECOT_SHA256[(arch, deb_release, package)]
+    except KeyError:
+        raise ValueError(f"no dovecot build for {pkg_name} on deb{deb_release}/{arch}")
 
+    stamped_version = _stamped_version(deb_release)
     installed_versions = host.get_fact(DebPackages).get(pkg_name, [])
-    if DOVECOT_PACKAGE_VERSION in installed_versions:
+    if f"1:{stamped_version}" in installed_versions:
         return None, False
 
-    url_version = DOVECOT_ARCHIVE_VERSION.replace("+", "%2B")
-    deb_base = f"{pkg_name}_{url_version}_{arch}.deb"
-    primary_url = f"https://download.delta.chat/dovecot/{deb_base}"
-    fallback_url = f"https://github.com/chatmail/dovecot/releases/download/upstream%2F{url_version}/{deb_base}"
+    # Primary URL: flat structure with distro suffix in filename
+    primary_deb = f"{pkg_name}_{stamped_version}_{arch}.deb"
+    primary_url = f"https://download.delta.chat/dovecot/{primary_deb}"
+    # GitHub release files: escaped + in filename; the release tag stays
+    # distro-neutral, both distros ship in one combined release
+    tag_version = DOVECOT_VERSION.replace("+", "%2B")
+    fallback_deb = f"{pkg_name}_{stamped_version.replace('+', '%2B')}_{arch}.deb"
+    fallback_url = (
+        f"https://github.com/chatmail/dovecot/releases/download/upstream%2F{tag_version}/{fallback_deb}"
+    )
     url = _pick_url(primary_url, fallback_url)
-    deb_filename = f"/root/{deb_base}"
+    deb_filename = f"/root/{primary_deb}"
 
     files.download(
         name=f"Download {pkg_name}",
@@ -134,6 +144,7 @@ def _download_dovecot_package(package: str, arch: str) -> tuple[str | None, bool
 
     return deb_filename, True
 
+
 def _configure_dovecot(deployer, config: Config, debug: bool = False):
     """Configures Dovecot IMAP server."""
     deployer.put_template(
@@ -143,7 +154,8 @@ def _configure_dovecot(deployer, config: Config, debug: bool = False):
         debug=debug,
         disable_ipv6=config.disable_ipv6,
     )
-    deployer.put_file("dovecot/auth.conf", "/etc/dovecot/auth.conf")
+    deployer.put_template("dovecot/auth.lua.j2", "/etc/dovecot/auth.lua", config=config)
+    deployer.remove_file("/etc/dovecot/auth.conf")
     deployer.put_file(
         "dovecot/push_notification.lua", "/etc/dovecot/push_notification.lua"
     )

cmdeploy/src/cmdeploy/dovecot/dovecot.conf.j2

@@ -7,6 +7,7 @@ listen = 0.0.0.0
 protocols = imap lmtp
 
 auth_mechanisms = plain
+auth_username_chars = abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@[]
 
 {% if debug == true %}
 auth_verbose = yes
@@ -36,11 +37,15 @@ default_client_limit = 20000
 # the following warning will be logged:
 #   Warning: service(imap): process_limit (1024) reached, client connections are being dropped
 service imap {
-  process_limit = 50000
+  process_limit = {{ config.max_imap_connections }}
 }
 
-mail_server_admin = mailto:root@{{ config.mail_domain }}
-mail_server_comment = Chatmail server
+{% if config.privacy_mail %}
+# Advertised to clients as IMAP METADATA /shared/admin (RFC 5464).
+# The privacy_mail contact from chatmail.ini is used because it is
+# the only address set by an operator.
+mail_server_admin = mailto:{{ config.privacy_mail }}
+{% endif %}
 
 # `zlib` enables compressing messages stored in the maildir.
 # See
@@ -56,12 +61,12 @@ imap_capability = +XDELTAPUSH XCHATMAIL
 
 # Authentication for system users.
 passdb {
-  driver = dict
-  args = /etc/dovecot/auth.conf
+  driver = lua
+  args = file=/etc/dovecot/auth.lua blocking=yes
 }
 userdb {
-  driver = dict
-  args = /etc/dovecot/auth.conf
+  driver = lua
+  args = file=/etc/dovecot/auth.lua blocking=yes
 }
 ##
 ## Mailbox locations and namespaces

cmdeploy/src/cmdeploy/external/deployer.py

@@ -1,4 +1,3 @@
-
 from pyinfra import host
 from pyinfra.facts.files import File
 
@@ -21,8 +20,8 @@ class ExternalTlsDeployer(Deployer):
     def configure(self):
         # Verify cert and key exist on the remote host using pyinfra facts.
         for path in (self.cert_path, self.key_path):
-                if host.get_fact(File, path=path) is None:
-                    raise Exception(f"External TLS file not found on server: {path}")
+            if host.get_fact(File, path=path) is None:
+                raise Exception(f"External TLS file not found on server: {path}")
 
         self.ensure_systemd_unit(
             "external/tls-cert-reload.path.j2",
@@ -40,5 +39,3 @@ class ExternalTlsDeployer(Deployer):
             running=True,
             enabled=True,
         )
-
-

cmdeploy/src/cmdeploy/filtermail/deployer.py

@@ -3,6 +3,7 @@ import os
 from pyinfra import facts, host
 
 from cmdeploy.basedeploy import Deployer
+from cmdeploy.pins import FILTERMAIL_ARTIFACTS
 
 
 class FiltermailDeployer(Deployer):
@@ -20,11 +21,7 @@ class FiltermailDeployer(Deployer):
             return
 
         arch = host.get_fact(facts.server.Arch)
-        url = f"https://github.com/chatmail/filtermail/releases/download/v0.6.4/filtermail-{arch}"
-        sha256sum = {
-            "x86_64": "5295115952c72e4c4ec3c85546e094b4155a4c702c82bd71fcdcb744dc73adf6",
-            "aarch64": "6892244f17b8f26ccb465766e96028e7222b3c8adefca9fc6bfe9ff332ca8dff",
-        }[arch]
+        url, sha256sum = FILTERMAIL_ARTIFACTS[arch]
         self.download_executable(url, self.bin_path, sha256sum)
 
     def configure(self):

cmdeploy/src/cmdeploy/filtermail/filtermail-transport.service.j2

@@ -6,6 +6,7 @@ ExecStart={{ bin_path }} {{ config_path }} transport
 Restart=always
 RestartSec=30
 User=vmail
+LimitNOFILE=524288
 
 [Install]
 WantedBy=multi-user.target

cmdeploy/src/cmdeploy/iroh-relay.service.j2

@@ -2,7 +2,7 @@
 Description=Iroh relay
 
 [Service]
-ExecStart=/usr/local/bin/iroh-relay --config-path /etc/iroh-relay.toml
+ExecStart={{ bin_path }} --config-path {{ config_path }}
 Restart=on-failure
 RestartSec=5s
 User=iroh

cmdeploy/src/cmdeploy/mtail/delivered_mail.mtail

@@ -28,6 +28,13 @@ counter created_nonci_accounts
   }
 }
 
+# doveauth refusing new addresses because a chatmail.ini
+# system resource limit is exceeded.
+counter rejected_registrations
+/registration rejected: / {
+  rejected_registrations++
+}
+
 counter postfix_timeouts
 /timeout after DATA/ {
   postfix_timeouts++
@@ -73,6 +80,11 @@ counter incoming_unencrypted_mail_count
   filtered_incoming_mail_count++
 }
 
+counter incoming_mailer_daemon_mail_count
+/Incoming: Filtering mailer-daemon message from/ {
+  incoming_mailer_daemon_mail_count++
+  filtered_incoming_mail_count++
+}
 
 counter rejected_unencrypted_mail_count
 /Rejected unencrypted mail/ {

cmdeploy/src/cmdeploy/mtail/deployer.py

@@ -1,10 +1,14 @@
 from pyinfra import facts, host
-from pyinfra.operations import apt
+from pyinfra.operations import apt, server
 
 from cmdeploy.basedeploy import Deployer
+from cmdeploy.pins import FILTERMAIL_ARTIFACTS, MTAIL_ARTIFACTS
 
 
 class MtailDeployer(Deployer):
+    bin_path = "/usr/local/bin/mtail"
+    progs_dir = "/etc/mtail"
+
     def __init__(self, mtail_address):
         self.mtail_address = mtail_address
 
@@ -12,19 +16,10 @@ class MtailDeployer(Deployer):
         # Uninstall mtail package to install a static binary.
         apt.packages(name="Uninstall mtail", packages=["mtail"], present=False)
 
-        (url, sha256sum) = {
-            "x86_64": (
-                "https://github.com/google/mtail/releases/download/v3.0.8/mtail_3.0.8_linux_amd64.tar.gz",
-                "d55cb601049c5e61eabab29998dbbcea95d480e5448544f9470337ba2eea882e",
-            ),
-            "aarch64": (
-                "https://github.com/google/mtail/releases/download/v3.0.8/mtail_3.0.8_linux_arm64.tar.gz",
-                "f748db8ad2a1e0b63684d4c8868cf6a373a20f7e6922e5ece601fff0ee00eb1a",
-            ),
-        }[host.get_fact(facts.server.Arch)]
+        (url, sha256sum) = MTAIL_ARTIFACTS[host.get_fact(facts.server.Arch)]
         self.download_executable(
             url,
-            "/usr/local/bin/mtail",
+            self.bin_path,
             sha256sum,
             extract="gunzip | tar -xf - mtail -O",
         )
@@ -36,8 +31,31 @@ class MtailDeployer(Deployer):
             "mtail/mtail.service.j2",
             address=self.mtail_address or "127.0.0.1",
             port=3903,
+            bin_path=self.bin_path,
+            progs_dir=self.progs_dir,
         )
-        self.put_file("mtail/delivered_mail.mtail", "/etc/mtail/delivered_mail.mtail")
+        if self.mtail_address:
+            self.put_file(
+                "mtail/delivered_mail.mtail", f"{self.progs_dir}/delivered_mail.mtail"
+            )
+            url, sha256sum = FILTERMAIL_ARTIFACTS['mtail']
+            self.download_executable(
+                url,
+                f"{self.progs_dir}/filtermail.mtail",
+                sha256sum,
+                mode="644",
+            )
+            if self.need_restart:
+                # Check if all installed mtail rules compile or fail early
+                # --one_shot to exit, --port 0 to not clash with running mtail.
+                server.shell(
+                    name="Validate mtail programs",
+                    commands=[
+                        f"timeout 30 {self.bin_path} --compile_only --one_shot"
+                        f" --progs {self.progs_dir} --logs /dev/null"
+                        " --address 127.0.0.1 --port 0"
+                    ],
+                )
 
     def activate(self):
         active = bool(self.mtail_address)

cmdeploy/src/cmdeploy/mtail/mtail.service.j2

@@ -5,7 +5,7 @@ Wants=network-online.target
 
 [Service]
 Type=simple
-ExecStart=/bin/sh -c "journalctl -f -o short-iso -n 0 | /usr/local/bin/mtail --address={{ address }} --port={{ port }} --progs /etc/mtail --logtostderr --logs -"
+ExecStart=/bin/sh -c "journalctl -f -o short-iso -n 0 | {{ bin_path }} --address={{ address }} --port={{ port }} --progs {{ progs_dir }} --logtostderr --logs -"
 Restart=on-failure
 RestartSec=2s
 

cmdeploy/src/cmdeploy/nginx/nginx.conf.j2

@@ -128,7 +128,10 @@ http {
                         proxy_set_header Connection "upgrade";
                 }
 
-		location /relay/probe {
+		# Endpoints Iroh uses for net_report probes and that clients
+		# probe to tell whether this relay works. Both paths are served
+		# by iroh-relay 0.35 and by the 1.0 line.
+		location /ping {
                         proxy_pass http://127.0.0.1:3340;
                         proxy_http_version 1.1;
 		}

cmdeploy/src/cmdeploy/pins.py

@@ -0,0 +1,73 @@
+"""Versions, hashes, and download URLs for pre-built artifacts fetched during deploy."""
+
+FILTERMAIL_VERSION = "v0.7.4"
+FILTERMAIL_ARTIFACTS = {
+    "x86_64": (
+        f"https://github.com/chatmail/filtermail/releases/download/{FILTERMAIL_VERSION}/filtermail-x86_64",
+        "484cb8dff083134aefba9fce4a6b7ef4784a0f0e28e5108ecf8bb9e58a44fd2c",
+    ),
+    "aarch64": (
+        f"https://github.com/chatmail/filtermail/releases/download/{FILTERMAIL_VERSION}/filtermail-aarch64",
+        "66aa0ca2ca9add7a12d92883d76f8786384092adfde24a3d3a1d0b1f30d23a9e",
+    ),
+    "mtail": (
+        f"https://raw.githubusercontent.com/chatmail/filtermail/{FILTERMAIL_VERSION}/contrib/filtermail.mtail",
+        "948f688bb89ad47e6eb0fc8fa107e201a689f5adc264ff926be487a2a8562b51",
+    ),
+}
+
+MTAIL_VERSION = "3.4.9"
+MTAIL_ARTIFACTS = {
+    "x86_64": (
+        f"https://github.com/jaqx0r/mtail/releases/download/v{MTAIL_VERSION}/mtail_{MTAIL_VERSION}_linux_amd64.tar.gz",
+        "55f64a87f71955bb871c724b4aadf19fe9d854e6327196919c7fe44943427eab",
+    ),
+    "aarch64": (
+        f"https://github.com/jaqx0r/mtail/releases/download/v{MTAIL_VERSION}/mtail_{MTAIL_VERSION}_linux_arm64.tar.gz",
+        "e0a2b66b372ca257d7daeb7ba10f9233a2192a1f9057618fccc6be5c854a2a3c",
+    ),
+}
+
+# distro-neutral base version, as committed in chatmail/dovecot debian/changelog
+DOVECOT_VERSION = "2.3.21+dfsg1-3+chatmail2"
+DOVECOT_SHA256 = {
+    ("amd64", 12, "auth-lua"): "ef1b8e1db45147a74b48d63125bd61b2cc2f250e1006656ba1c58b9c12f5cde6",
+    ("arm64", 12, "auth-lua"): "c1a06ee9374439893e397ba3b0cacf532a733290c184f4f30ea39df8699be329",
+    ("amd64", 13, "auth-lua"): "6c0946d2516efcbcaa09a27df9b8ea701861cce270d71941056b3c69831a5ea2",
+    ("arm64", 13, "auth-lua"): "5e6c9cfe47f7f3b8aa0d68a3e607161b6abaee1ad696cb1419e997b3099b2985",
+    ("amd64", 12, "core"): "ac3977264d9b9a6fcec53fd3f5cdd2a79ca8aa0324de530c07e535008540826e",
+    ("arm64", 12, "core"): "21626c9c9b52cbdcf1a17b5c09e3c4043e69aa371bf83cc2fcb3b7ddaecdc109",
+    ("amd64", 13, "core"): "47c242ef23c17e700ac19d52d82c9fdb2ebd757d8beb3a7f6781d2de59f87bd0",
+    ("arm64", 13, "core"): "c14c53f112c875f698c4cb6e5870c605cd0a9dd98d35a66e94ceb1827f8020a3",
+    ("amd64", 12, "imapd"): "92a7ab5fc7dc32886a0c34404f919f1335d397b48c467e0c1ef77e56978f60ea",
+    ("arm64", 12, "imapd"): "9369fd566fec4df109ef23debf34ea0417ae85beb29cbe7de619d4d1f31b120c",
+    ("amd64", 13, "imapd"): "e38cc1266455f937ed62f971ea859c47e1a99247841ed0ad946963b524cfdbc5",
+    ("arm64", 13, "imapd"): "11d97dabf23171b37f8b1335dfdb81d408f8b95391aea6d4066aecc9fde01dfe",
+    ("amd64", 12, "lmtpd"): "dc3de473789969f7dd3504ac8783da5e42a446d2d7a305a4e9d7081a6dfe71ab",
+    ("arm64", 12, "lmtpd"): "ae2cbd6c5c43f6d8e2172997b055448f4c79238e2f99cd9ab9200a7d9f548908",
+    ("amd64", 13, "lmtpd"): "833b243e28c7baff141ecf37456e310f5d836e7944a3b9f2fe5074adf0d6a418",
+    ("arm64", 13, "lmtpd"): "55af47a121ba7e23966b20ddaab2dff7feba4b34677864e045e31a702afa180d",
+}
+TURN_VERSION = "v0.4"
+TURN_ARTIFACTS = {
+    "x86_64": (
+        f"https://github.com/chatmail/chatmail-turn/releases/download/{TURN_VERSION}/chatmail-turn-x86_64-linux",
+        "1ec1f5c50122165e858a5a91bcba9037a28aa8cb8b64b8db570aa457c6141a8a",
+    ),
+    "aarch64": (
+        f"https://github.com/chatmail/chatmail-turn/releases/download/{TURN_VERSION}/chatmail-turn-aarch64-linux",
+        "0fb3e792419494e21ecad536464929dba706bb2c88884ed8f1788141d26fc756",
+    ),
+}
+
+IROH_VERSION = "v0.35.0"
+IROH_ARTIFACTS = {
+    "x86_64": (
+        f"https://github.com/n0-computer/iroh/releases/download/{IROH_VERSION}/iroh-relay-{IROH_VERSION}-x86_64-unknown-linux-musl.tar.gz",
+        "45c81199dbd70f8c4c30fef7f3b9727ca6e3cea8f2831333eeaf8aa71bf0fac1",
+    ),
+    "aarch64": (
+        f"https://github.com/n0-computer/iroh/releases/download/{IROH_VERSION}/iroh-relay-{IROH_VERSION}-aarch64-unknown-linux-musl.tar.gz",
+        "f8ef27631fac213b3ef668d02acd5b3e215292746a3fc71d90c63115446008b1",
+    ),
+}

cmdeploy/src/cmdeploy/postfix/main.cf.j2

@@ -53,15 +53,19 @@ smtpd_tls_exclude_ciphers = aNULL, RC4, MD5, DES
 # See <https://www.postfix.org/FORWARD_SECRECY_README.html#server_fs>.
 tls_preempt_cipherlist = yes
 
-smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
-myhostname = {{ config.mail_domain }}
+# Reject by default, override per smtpd in master.cf
+smtpd_relay_restrictions = reject
+myhostname = {{ config.postfix_myhostname }}
 alias_maps = hash:/etc/aliases
 alias_database = hash:/etc/aliases
 
-# Postfix does not deliver mail for any domain by itself.
-# Primary domain is listed in `virtual_mailbox_domains` instead
-# and handed over to Dovecot.
-mydestination =
+# When postfix receives mail for $mydestination,
+# it hands it over to dovecot via $local_transport.
+# Note: IP literals must be handled via local delivery / mydestination.
+mydestination = {{ config.mail_domain }}
+local_transport = lmtp:unix:private/dovecot-lmtp
+# postfix doesn't check whether local users exist or not:
+local_recipient_maps =
 
 relayhost = 
 {% if disable_ipv6 %}
@@ -79,10 +83,16 @@ inet_protocols = ipv4
 inet_protocols = all
 {% endif %}
 
-virtual_transport = lmtp:unix:private/dovecot-lmtp
-virtual_mailbox_domains = {{ config.mail_domain }}
 lmtp_header_checks = regexp:/etc/postfix/lmtp_header_cleanup
 
+# Do not apply header checks to MIME headers
+# and other headers that are actually part of the message body.
+# Reference:
+# <https://www.postfix.org/postconf.5.html#disable_mime_input_processing>
+# <https://www.postfix.org/header_checks.5.html>
+# <https://stump.io/blog/2020/11/29/a-little-gotcha-with-postfixs-header_checks/>
+disable_mime_input_processing = yes
+
 mua_client_restrictions = permit_sasl_authenticated, reject
 mua_sender_restrictions = reject_sender_login_mismatch, permit_sasl_authenticated, reject
 mua_helo_restrictions = permit_mynetworks, reject_invalid_helo_hostname, reject_non_fqdn_helo_hostname, permit
@@ -100,5 +110,28 @@ smtpd_peername_lookup = no
 # so instead this is handled in filtermail.
 # We use LMTP instead SMTP so we can communicate per-recipient errors back to postfix.
 default_transport = lmtp-filtermail:inet:[127.0.0.1]:{{ config.filtermail_lmtp_port_transport }}
+
+# All deliveries over lmtp-filtermail are treated
+# as having the same destination [127.0.0.1],
+# so it is not possible to limit per-destination concurrency here,
+# it is a job for filtermail-transport.
+# Total number of parallel deliveries is limited
+# by "maxproc" column in /etc/postfix/master.cf for lmtp-filtermail.
+# Settings below are to prevent Postfix queue manager
+# from limiting the number of LMTP connections to filtermail-transport.
+# Read <https://www.postfix.org/TUNING_README.html#rope> and
+# <https://www.postfix.org/SCHEDULER_README.html> for the details
+# of the Postfix algorithm that we effectively disable here.
 lmtp-filtermail_initial_destination_concurrency=10000
 lmtp-filtermail_destination_concurrency_limit=10000
+
+# Do not try to deliver messages for more than 2 days.
+maximal_queue_lifetime = 2d
+
+{% if not config.ipv4_relay %}
+# DKIM-sign locally generated mail (bounces, DSNs).
+# These bypass smtpd, so they need explicit milter configuration.
+non_smtpd_milters = unix:opendkim/opendkim.sock
+internal_mail_filter_classes = bounce
+milter_macro_daemon_name = ORIGINATING
+{% endif %}

cmdeploy/src/cmdeploy/postfix/master.cf.j2

@@ -17,7 +17,8 @@ smtp      inet  n       -       y       -       -       smtpd
   -o smtpd_tls_security_level=encrypt
   -o smtpd_tls_mandatory_protocols=>=TLSv1.2
   -o smtpd_proxy_filter=127.0.0.1:{{ config.filtermail_smtp_port_incoming }}
-submission inet n       -       y       -       5000    smtpd
+  -o smtpd_relay_restrictions=reject_unauth_destination
+submission inet n       -       y       -       {{ config.max_smtp_connections }}    smtpd
   -o syslog_name=postfix/submission
   -o smtpd_tls_security_level=encrypt
   -o smtpd_tls_mandatory_protocols=>=TLSv1.3
@@ -31,9 +32,9 @@ submission inet n       -       y       -       5000    smtpd
   -o smtpd_sender_restrictions=$mua_sender_restrictions
   -o smtpd_recipient_restrictions=
   -o smtpd_relay_restrictions=permit_sasl_authenticated,reject
-  -o smtpd_client_connection_count_limit=1000
+  -o smtpd_client_connection_count_limit={{ config.max_smtp_connections // 5 }}
   -o smtpd_proxy_filter=127.0.0.1:{{ config.filtermail_smtp_port }}
-smtps     inet  n       -       y       -       5000    smtpd
+smtps     inet  n       -       y       -       {{ config.max_smtp_connections }}    smtpd
   -o syslog_name=postfix/smtps
   -o smtpd_tls_wrappermode=yes
   -o smtpd_tls_security_level=encrypt
@@ -47,7 +48,7 @@ smtps     inet  n       -       y       -       5000    smtpd
   -o smtpd_sender_restrictions=$mua_sender_restrictions
   -o smtpd_recipient_restrictions=
   -o smtpd_relay_restrictions=permit_sasl_authenticated,reject
-  -o smtpd_client_connection_count_limit=1000
+  -o smtpd_client_connection_count_limit={{ config.max_smtp_connections // 5 }}
   -o smtpd_proxy_filter=127.0.0.1:{{ config.filtermail_smtp_port }}
 #628       inet  n       -       y       -       -       qmqpd
 pickup    unix  n       -       y       60      1       pickup
@@ -75,17 +76,19 @@ lmtp      unix  -       -       y       -       -       lmtp
 anvil     unix  -       -       y       -       1       anvil
 scache    unix  -       -       y       -       1       scache
 postlog   unix-dgram n  -       n       -       1       postlogd
-filter    unix -        n       n       -       -       lmtp
 # Local SMTP server for reinjecting outgoing filtered mail.
 127.0.0.1:{{ config.postfix_reinject_port }} inet  n       -       n       -       100      smtpd
   -o syslog_name=postfix/reinject
   -o milter_macro_daemon_name=ORIGINATING
-  -o smtpd_milters=unix:opendkim/opendkim.sock
   -o cleanup_service_name=authclean
+  -o smtpd_relay_restrictions=permit_mynetworks,reject
+{% if not config.ipv4_relay %}  -o smtpd_milters=unix:opendkim/opendkim.sock
+{% endif %}
 
 # Local SMTP server for reinjecting incoming filtered mail 
 127.0.0.1:{{ config.postfix_reinject_port_incoming }} inet  n       -       n       -       100      smtpd
   -o syslog_name=postfix/reinject_incoming
+  -o smtpd_relay_restrictions=reject_unauth_destination
 
 # Cleanup `Received` headers for authenticated mail
 # to avoid leaking client IP.
@@ -101,7 +104,15 @@ filter    unix -        n       n       -       -       lmtp
 authclean unix  n       -       -       -       0       cleanup
   -o header_checks=regexp:/etc/postfix/submission_header_cleanup
 
-lmtp-filtermail unix  -       -       y       -       10000       lmtp
+# Reducing `maxproc` here may result in a head of line blocking
+# when there are many messages sent to unreachable destinations
+# at the same time.
+# LMTP clients here talk to filtermail-transport.
+# LMTP has no pipelining,
+# so while filtermail-transport tries to deliver the message,
+# possibly waiting for a long connection timeout
+# or talking to a slow server, LMTP client cannot be reused.
+lmtp-filtermail unix  -       -       y       -       500       lmtp
   -o syslog_name=postfix/lmtp-filtermail
   -o lmtp_header_checks=
   -o lmtp_tls_security_level=none

cmdeploy/src/cmdeploy/service/chatmail-expire.service.f

@@ -5,5 +5,5 @@ After=network.target
 [Service]
 Type=oneshot
 User=vmail
-ExecStart=/usr/local/lib/chatmaild/venv/bin/chatmail-expire /usr/local/lib/chatmaild/chatmail.ini -v --remove
+ExecStart={execpath} {config_path} -v --remove
 

cmdeploy/src/cmdeploy/service/chatmail-fsreport.service.f

@@ -5,5 +5,5 @@ After=network.target
 [Service]
 Type=oneshot
 User=vmail
-ExecStart=/usr/local/lib/chatmaild/venv/bin/chatmail-fsreport /usr/local/lib/chatmaild/chatmail.ini
+ExecStart={execpath} {config_path}
 

cmdeploy/src/cmdeploy/service/doveauth.service.f

@@ -1,12 +1,11 @@
 [Unit]
-Description=Chatmail dict authentication proxy for dovecot
+Description=Chatmail HTTP authentication service for dovecot
 
 [Service]
-ExecStart={execpath} /run/doveauth/doveauth.socket {config_path}
+ExecStart={execpath} {config_path}
 Restart=always
-RestartSec=30
+RestartSec=5
 User=vmail
-RuntimeDirectory=doveauth
 UMask=0077
 
 [Install]

cmdeploy/src/cmdeploy/service/turnserver.service.f

@@ -5,7 +5,7 @@ After=network.target
 [Service]
 Type=simple
 Restart=always
-ExecStart=/usr/local/bin/chatmail-turn --realm {mail_domain} --socket /run/chatmail-turn/turn.socket
+ExecStart={bin_path} --realm {mail_domain} --socket /run/chatmail-turn/turn.socket
 
 # Create /run/chatmail-turn
 RuntimeDirectory=chatmail-turn

cmdeploy/src/cmdeploy/tests/conftest.py

@@ -0,0 +1,27 @@
+"""Run the lua scripts we ship under lupa, which bundles Lua 5.4 like dovecot."""
+
+import pytest
+from chatmaild.tests.plugin import *  # noqa: F403
+from lupa import lua54
+
+from cmdeploy.basedeploy import get_resource
+from cmdeploy.tests.plugin import *  # noqa: F403
+
+
+class Lua:
+    """A Lua runtime to load shipped scripts and mocks into."""
+
+    def __init__(self):
+        self.rt = lua54.LuaRuntime(unpack_returned_tuples=True)
+        self.g = self.rt.globals()
+
+    def load(self, path):
+        self.rt.execute(get_resource(path).read_text())
+
+    def table(self, **kwargs):
+        return self.rt.table(**kwargs)
+
+
+@pytest.fixture
+def lua():
+    return Lua()

cmdeploy/src/cmdeploy/tests/online/test_0_login.py

@@ -12,7 +12,7 @@ def test_init(tmp_path, maildomain):
     inipath = tmp_path.joinpath("chatmail.ini")
     main(["init", "--config", str(inipath), maildomain])
     config = read_config(inipath)
-    assert config.mail_domain == maildomain
+    assert config.mail_domain_bare == maildomain
 
 
 def test_capabilities(imap):
@@ -89,12 +89,11 @@ def test_concurrent_logins_same_account(
         assert login_results.get()
 
 
-def test_no_vrfy(cmfactory, chatmail_config):
+def test_no_vrfy(cmfactory, chatmail_config, maildomain):
     ac = cmfactory.get_online_account()
     addr = ac.get_config("addr")
-    domain = chatmail_config.mail_domain
 
-    s = smtplib.SMTP(domain)
+    s = smtplib.SMTP(maildomain)
     s.starttls()
 
     s.putcmd("vrfy", f"wrongaddress@{chatmail_config.mail_domain}")

cmdeploy/src/cmdeploy/tests/online/test_0_qr.py

@@ -20,17 +20,17 @@ def test_fastcgi_working(maildomain, chatmail_config):
 
 
 @pytest.mark.filterwarnings("ignore::urllib3.exceptions.InsecureRequestWarning")
-def test_newemail_configure(maildomain, rpc, chatmail_config):
+def test_newemail_configure(maildomain, cmrpc, chatmail_config):
     """Test configuring accounts by scanning a QR code works."""
     url = f"DCACCOUNT:https://{maildomain}/new"
     for i in range(3):
-        account_id = rpc.add_account()
+        account_id = cmrpc.add_account()
         if chatmail_config.tls_cert_mode == "self":
             # deltachat core's rustls rejects self-signed HTTPS certs during
             # set_config_from_qr, so fetch credentials via requests instead
             res = requests.post(f"https://{maildomain}/new", verify=False)
             data = res.json()
-            rpc.add_or_update_transport(account_id, {
+            cmrpc.add_or_update_transport(account_id, {
                 "addr": data["email"],
                 "password": data["password"],
                 "imapServer": maildomain,
@@ -38,4 +38,4 @@ def test_newemail_configure(maildomain, rpc, chatmail_config):
                 "certificateChecks": "acceptInvalidCertificates",
             })
         else:
-            rpc.add_transport_from_qr(account_id, url)
+            cmrpc.add_transport_from_qr(account_id, url)

cmdeploy/src/cmdeploy/tests/online/test_1_basic.py

@@ -5,6 +5,7 @@ import subprocess
 import time
 
 import pytest
+from chatmaild.config import is_valid_ipv4
 
 from cmdeploy import remote
 from cmdeploy.cmdeploy import get_sshexec
@@ -21,6 +22,8 @@ class TestSSHExecutor:
         assert out == out2
 
     def test_perform_initial(self, sshexec, maildomain):
+        if is_valid_ipv4(maildomain):
+            pytest.skip(f"{maildomain} is not a domain")
         res = sshexec(
             remote.rdns.perform_initial_checks, kwargs=dict(mail_domain=maildomain)
         )
@@ -61,8 +64,10 @@ class TestSSHExecutor:
         else:
             pytest.fail("didn't raise exception")
 
-    def test_opendkim_restarted(self, sshexec):
+    def test_opendkim_restarted(self, sshexec, maildomain):
         """check that opendkim is not running for longer than a day."""
+        if is_valid_ipv4(maildomain):
+            pytest.skip(f"{maildomain} is an IPv4 relay, opendkim is not installed")
         cmd = "systemctl show opendkim --timestamp=utc --property=ActiveEnterTimestamp"
         out = sshexec(call=remote.rshell.shell, kwargs=dict(command=cmd))
         datestring = out.split("=")[1]
@@ -189,6 +194,34 @@ def test_reject_missing_dkim(cmsetup, maildata, from_addr):
             s.sendmail(from_addr=from_addr, to_addrs=recipient.addr, msg=msg)
 
 
+def test_bounces_are_dkim_signed(cmsetup, cmsetup2, maildata, maildomain):
+    # we send a message to non-existant user and expect a bounce message
+    # which will only get through if the bounce message was DKIM-signed
+
+    if is_valid_ipv4(maildomain):
+        pytest.skip("DKIM is not configured on IPv4-only relays")
+
+    sender = cmsetup2.gen_users(1)[0]
+    nonexistent = f"nosuchuser_test42@{cmsetup.maildomain}"
+
+    msg = maildata(
+        "encrypted.eml",
+        from_addr=sender.addr,
+        to_addr=nonexistent,
+    ).as_string()
+    sender.smtp.sendmail(sender.addr, [nonexistent], msg)
+
+    def bounce_in_inbox():
+        messages = sender.imap.fetch_all_messages()
+        for m in messages:
+            if "mail delivery" in m.lower() or "undelivered" in m.lower():
+                return m
+        raise ValueError("bounce not yet in inbox")
+
+    bounce = try_n_times(30, bounce_in_inbox)
+    assert "nosuchuser_test42" in bounce
+
+
 def try_n_times(n, f):
     for _ in range(n - 1):
         try:
@@ -290,4 +323,6 @@ def test_nginx_access_log_only_defined_once(sshdomain):
         kwargs=dict(command="nginx -T 2>/dev/null"),
     )
     access_logs = [l for l in conf.splitlines() if l.strip().startswith("access_log")]
-    assert len(access_logs) == 1, f"expected 1 access_log, found {len(access_logs)}: {access_logs}"
+    assert len(access_logs) == 1, (
+        f"expected 1 access_log, found {len(access_logs)}: {access_logs}"
+    )

cmdeploy/src/cmdeploy/tests/online/test_2_deltachat.py

@@ -1,10 +1,12 @@
 import ipaddress
+import json
 import re
 import time
 
 import imap_tools
 import pytest
 import requests
+from chatmaild.tests.test_appversions import check_appversions
 
 from cmdeploy.cmdeploy import get_sshexec
 from cmdeploy.remote import rshell
@@ -15,7 +17,7 @@ def imap_mailbox(cmfactory, ssl_context):
     (ac1,) = cmfactory.get_online_accounts(1)
     user = ac1.get_config("addr")
     password = ac1.get_config("mail_pw")
-    host = user.split("@")[1]
+    host = user.split("@")[1].strip("[").strip("]")
     mailbox = imap_tools.MailBox(host, ssl_context=ssl_context)
     mailbox.login(user, password)
     mailbox.dc_ac = ac1
@@ -51,6 +53,17 @@ class TestMetadataTokens:
         assert res == b"1111 2222"
         assert b"Getmetadata completed" in client.readline()
 
+    def test_get_appversions(self, imap_mailbox):
+        "get app version information shipped with the relay"
+        client = imap_mailbox.client
+        client.send(b'a01 GETMETADATA "" /shared/vendor/deltachat/appversions\n')
+        res = client.readline()
+        assert res[:1] == b"*"
+        res = client.readline().strip().rstrip(b")")
+        # the served value is a single line and passes the shipped file's schema
+        check_appversions(json.loads(res))
+        assert b"Getmetadata completed" in client.readline()
+
 
 class TestEndToEndDeltaChat:
     "Tests that use Delta Chat accounts on the chat mail instance."
@@ -178,7 +191,7 @@ def test_hide_senders_ip_address(cmfactory, ssl_context):
     chat.send_text("testing submission header cleanup")
     user2.wait_for_incoming_msg()
     addr = user2.get_config("addr")
-    host = addr.split("@")[1]
+    host = addr.split("@")[1].strip("[").strip("]")
     pw = user2.get_config("mail_pw")
     mailbox = imap_tools.MailBox(host, ssl_context=ssl_context)
     mailbox.login(addr, pw)

cmdeploy/src/cmdeploy/tests/plugin.py

@@ -1,5 +1,4 @@
 import imaplib
-import ipaddress
 import itertools
 import os
 import random
@@ -10,24 +9,17 @@ import time
 from pathlib import Path
 
 import pytest
-from chatmaild.config import read_config
-
-conftestdir = Path(__file__).parent
+from chatmaild.config import is_valid_ipv4, read_config
 
 
-def _is_ip(domain):
-    try:
-        ipaddress.ip_address(domain)
-        return True
-    except ValueError:
-        return False
+def format_mail_domain(raw_domain: str) -> str:
+    if is_valid_ipv4(raw_domain):
+        return f"[{raw_domain}]"
+    return raw_domain
 
 
 def pytest_configure(config):
     config._benchresults = {}
-    config.addinivalue_line(
-        "markers", "slow: mark test to require --slow option to run"
-    )
 
 
 def _get_chatmail_config():
@@ -58,7 +50,7 @@ def chatmail_config(pytestconfig):
 
 @pytest.fixture(scope="session")
 def maildomain(chatmail_config):
-    return chatmail_config.mail_domain
+    return chatmail_config.mail_domain_bare
 
 
 @pytest.fixture(scope="session")
@@ -213,7 +205,7 @@ class ImapConn:
         status, res = self.conn.select()
         if int(res[0]) == 0:
             raise ValueError("no messages in imap folder")
-        status, results = self.conn.fetch("1:*", "(RFC822)")
+        status, results = self.conn.fetch("1:*", "(BODY.PEEK[])")
         assert status == "OK"
         return results
 
@@ -278,7 +270,6 @@ def gencreds(chatmail_config):
 
     def gen(domain=None):
         domain = domain if domain else chatmail_config.mail_domain
-        addr_domain = f"[{domain}]" if _is_ip(domain) else domain
         while 1:
             num = next(count)
             alphanumeric = "abcdefghijklmnopqrstuvwxyz1234567890"
@@ -292,7 +283,7 @@ def gencreds(chatmail_config):
             password = "".join(
                 random.choices(alphanumeric, k=chatmail_config.password_min_length)
             )
-            yield f"{user}@{addr_domain}", f"{password}"
+            yield f"{user}@{domain}", f"{password}"
 
     return lambda domain=None: next(gen(domain))
 
@@ -317,7 +308,8 @@ class ChatmailACFactory:
 
     def _make_transport(self, domain):
         """Build a transport config dict for the given domain."""
-        addr, password = self.gencreds(domain)
+        domain_deliverable = format_mail_domain(domain)
+        addr, password = self.gencreds(domain_deliverable)
         transport = {
             "addr": addr,
             "password": password,
@@ -326,7 +318,7 @@ class ChatmailACFactory:
             "imapServer": domain,
             "smtpServer": domain,
         }
-        if self.chatmail_config.tls_cert_mode == "self":
+        if domain.startswith("_") or is_valid_ipv4(domain):
             transport["certificateChecks"] = "acceptInvalidCertificates"
         return transport
 
@@ -341,16 +333,17 @@ class ChatmailACFactory:
         accounts = []
         for _ in range(num):
             account = self.dc.add_account()
-            addr, password = self.gencreds(domain)
-            if _is_ip(domain):
+            domain_deliverable = format_mail_domain(domain)
+            addr, password = self.gencreds(domain_deliverable)
+            if is_valid_ipv4(domain):
                 # Use DCLOGIN scheme with explicit server hosts,
                 # matching how madmail presents its addresses to users.
                 qr = (
                     f"dclogin:{addr}"
                     f"?p={password}&v=1"
-                    f"&ih={domain}&ip=993"
-                    f"&sh={domain}&sp=465"
-                    f"&ic=3&ss=default"
+                    f"&ih={domain}&ip=993&is=ssl"
+                    f"&sh={domain}&sp=465&ss=ssl"
+                    f"&ic=3"
                 )
                 future = account.add_transport_from_qr.future(qr)
             else:
@@ -361,7 +354,7 @@ class ChatmailACFactory:
 
             # ensure messages stay in INBOX so that they can be
             # concurrently fetched via extra IMAP connections during tests
-            account.set_config("delete_server_after", "10")
+            account.set_config("bcc_self", "1")
             accounts.append(account)
 
         for future in futures:
@@ -378,8 +371,12 @@ class ChatmailACFactory:
 
 
 @pytest.fixture(scope="session")
-def rpc(tmp_path_factory):
-    """Start a deltachat-rpc-server process for the test session."""
+def cmrpc(tmp_path_factory):
+    """Start a deltachat-rpc-server process for the test session.
+
+    Not named "rpc": the deltachat-rpc-client pytest plugin registers a
+    function-scoped fixture under that name and would shadow this one.
+    """
 
     # NB: accounts_dir must NOT already exist as directory --
     # core-rust only creates accounts.toml if the dir doesn't exist yet.
@@ -391,10 +388,10 @@ def rpc(tmp_path_factory):
 
 
 @pytest.fixture
-def cmfactory(rpc, gencreds, maildomain, chatmail_config):
+def cmfactory(cmrpc, gencreds, maildomain, chatmail_config):
     """Return a ChatmailACFactory for creating online Delta Chat accounts."""
     return ChatmailACFactory(
-        rpc=rpc,
+        rpc=cmrpc,
         maildomain=maildomain,
         gencreds=gencreds,
         chatmail_config=chatmail_config,
@@ -416,10 +413,10 @@ class Remote:
     def iter_output(self, logcmd="", ready=None):
         getjournal = "journalctl -f" if not logcmd else logcmd
         print(self.sshdomain)
-        match self.sshdomain:
-            case "@local": command = []
-            case "localhost": command = []
-            case _: command = ["ssh", f"root@{self.sshdomain}"]
+        if self.sshdomain in ("@local", "localhost"):
+            command = []
+        else:
+            command = ["ssh", f"root@{self.sshdomain}"]
         [command.append(arg) for arg in getjournal.split()]
         popen = subprocess.Popen(
             command,
@@ -466,6 +463,11 @@ def cmsetup(maildomain, gencreds, ssl_context):
     return CMSetup(maildomain, gencreds, ssl_context)
 
 
+@pytest.fixture
+def cmsetup2(maildomain2, gencreds, ssl_context):
+    return CMSetup(maildomain2, gencreds, ssl_context)
+
+
 class CMSetup:
     def __init__(self, maildomain, gencreds, ssl_context):
         self.maildomain = maildomain
@@ -476,7 +478,7 @@ class CMSetup:
         print(f"Creating {num} online users")
         users = []
         for i in range(num):
-            addr, password = self.gencreds()
+            addr, password = self.gencreds(format_mail_domain(self.maildomain))
             user = CMUser(self.maildomain, addr, password, self.ssl_context)
             assert user.smtp
             users.append(user)

cmdeploy/src/cmdeploy/tests/pytest.ini

@@ -1,2 +0,0 @@
-[pytest]
-addopts = -vrsx --strict-markers

cmdeploy/src/cmdeploy/tests/test_authlua.py

@@ -0,0 +1,216 @@
+"""Test auth.lua script against mocked dovecot auth API."""
+
+import jinja2
+import pytest
+from chatmaild.doveauth import encrypt_password, verify_password
+
+from cmdeploy.basedeploy import get_resource
+
+USER1 = "user12345@chat.example.org"
+USER2 = "newuser12@chat.example.org"
+OK, UNKNOWN, MISMATCH, INTERNAL = 1, -2, -3, -4
+
+DOVECOT_MOCKS = """
+create_status = 200
+
+dovecot = {
+  auth = {
+    PASSDB_RESULT_OK = OK,
+    PASSDB_RESULT_USER_UNKNOWN = UNKNOWN,
+    PASSDB_RESULT_PASSWORD_MISMATCH = MISMATCH,
+    PASSDB_RESULT_INTERNAL_FAILURE = INTERNAL,
+    USERDB_RESULT_OK = OK,
+    USERDB_RESULT_USER_UNKNOWN = UNKNOWN,
+  },
+  http = {
+    client = function(options)
+      client_options = options
+      return {request = function(_, options)
+        create_request = options
+        return {
+          set_payload = function(_, payload) create_payload = payload end,
+          submit = function()
+            return {status = function() return create_status end}
+          end,
+        }
+      end}
+    end,
+  },
+}
+"""
+
+
+def load_authlua(lua, config):
+    lua.g.OK, lua.g.UNKNOWN = OK, UNKNOWN
+    lua.g.MISMATCH, lua.g.INTERNAL = MISMATCH, INTERNAL
+    lua.rt.execute(DOVECOT_MOCKS)
+    template = jinja2.Template(get_resource("dovecot/auth.lua.j2").read_text())
+    lua.rt.execute(template.render(config=config))
+    assert lua.g.script_init() == 0
+    return lua
+
+
+@pytest.fixture
+def authlua(lua, example_config):
+    return load_authlua(lua, example_config)
+
+
+@pytest.fixture
+def request_for(lua):
+    def request_for(addr):
+        def password_verify(_self, hashed, plain):
+            return 1 if verify_password(hashed, plain) else 0
+
+        return lua.table(user=addr, password_verify=password_verify)
+
+    return request_for
+
+
+@pytest.fixture
+def create_user(example_config):
+    def create_user(addr, password):
+        example_config.get_user(addr).set_password(encrypt_password(password))
+
+    return create_user
+
+
+@pytest.fixture
+def write_password_file(example_config):
+    def write_password_file(addr, content):
+        maildir = example_config.mailboxes_dir / addr
+        maildir.mkdir(parents=True, exist_ok=True)
+        maildir.joinpath("password").write_text(content)
+
+    return write_password_file
+
+
+def test_http_client_uses_dovecot_setting_names(authlua):
+    """dovecot's lua http binding silently ignores keys it does not know."""
+    assert dict(authlua.g.client_options) == {
+        "request_timeout_msecs": 5000,
+        "max_attempts": 1,
+    }
+
+
+def test_existing_address_correct_password(authlua, request_for, create_user):
+    create_user(USER1, "correctgoose")
+    res, fields = authlua.g.auth_password_verify(request_for(USER1), "correctgoose")
+    assert res == OK
+    assert fields["uid"] == fields["gid"] == "vmail"
+    assert fields["home"].endswith(USER1)
+    assert authlua.g.create_payload is None
+
+
+def test_existing_address_wrong_password(authlua, request_for, create_user):
+    create_user(USER1, "correctgoose")
+    res, _ = authlua.g.auth_password_verify(request_for(USER1), "wronghorse")
+    assert res == MISMATCH
+
+
+def test_foreign_domain_is_refused_without_calling_out(
+    authlua, request_for, create_user
+):
+    create_user("user12345@evil.example.org", "correctgoose")
+    request = request_for("user12345@evil.example.org")
+    res, _ = authlua.g.auth_password_verify(request, "correctgoose")
+    assert res == UNKNOWN
+    assert authlua.g.auth_userdb_lookup(request)[0] == UNKNOWN
+    assert authlua.g.create_payload is None
+
+
+def test_name_shorter_than_the_domain_is_refused(authlua, request_for):
+    for name in ("x", "", "chat.example.org"):
+        res, _ = authlua.g.auth_password_verify(request_for(name), "correctgoose")
+        assert res == UNKNOWN
+        assert authlua.g.auth_userdb_lookup(request_for(name))[0] == UNKNOWN
+    assert authlua.g.create_payload is None
+
+
+def test_slash_in_username_is_refused(authlua, request_for):
+    request = request_for("../../etc/shadow@chat.example.org")
+    res, _ = authlua.g.auth_password_verify(request, "somepassword")
+    assert res == UNKNOWN
+    assert authlua.g.auth_userdb_lookup(request)[0] == UNKNOWN
+    assert authlua.g.create_payload is None
+
+
+def test_localpart_policy_is_left_to_doveauth(authlua, request_for):
+    authlua.g.create_status = 403
+    res, _ = authlua.g.auth_password_verify(request_for("@chat.example.org"), "somepw")
+    assert res == UNKNOWN
+    assert authlua.g.create_payload == "@chat.example.org\tsomepw"
+
+
+def test_unknown_address_is_created_via_endpoint(authlua, request_for):
+    res, fields = authlua.g.auth_password_verify(request_for(USER2), "brandnewpass")
+    assert res == OK
+    assert fields["home"].endswith(USER2)
+    assert authlua.g.create_payload == f"{USER2}\tbrandnewpass"
+    assert authlua.g.create_request["url"] == "http://127.0.0.1:10084/create"
+
+
+# doveauth refusing is the user's problem, doveauth failing is ours
+@pytest.mark.parametrize("status", [400, 403, 404])
+def test_creation_refused_by_doveauth_is_user_unknown(authlua, request_for, status):
+    authlua.g.create_status = status
+    res, _ = authlua.g.auth_password_verify(request_for(USER2), "brandnewpass")
+    assert res == UNKNOWN
+
+
+# 9003 is dovecot's own CONNECT_FAILED, what a stopped doveauth actually yields
+@pytest.mark.parametrize("status", [500, 502, 9003, 9005])
+def test_creation_that_doveauth_could_not_answer_is_internal_failure(
+    authlua, request_for, status
+):
+    authlua.g.create_status = status
+    res, _ = authlua.g.auth_password_verify(request_for(USER2), "brandnewpass")
+    assert res == INTERNAL
+
+
+def test_userdb_unknown_before_creation_ok_after(authlua, request_for, create_user):
+    request = request_for(USER1)
+    res, _ = authlua.g.auth_userdb_lookup(request)
+    assert res == UNKNOWN
+    # a userdb lookup must never create anything
+    assert authlua.g.create_payload is None
+
+    create_user(USER1, "correctgoose")
+    res, fields = authlua.g.auth_userdb_lookup(request)
+    assert res == OK
+    assert fields["home"].endswith(USER1)
+    assert fields["uid"] == fields["gid"] == "vmail"
+
+
+def test_empty_password_file_is_unknown(authlua, request_for, write_password_file):
+    write_password_file(USER1, "")
+    assert authlua.g.auth_userdb_lookup(request_for(USER1))[0] == UNKNOWN
+
+    write_password_file(USER1, "\n")
+    assert authlua.g.auth_userdb_lookup(request_for(USER1))[0] == UNKNOWN
+
+
+def test_password_file_format_checks(authlua, request_for, write_password_file):
+    write_password_file(USER1, encrypt_password("correctgoose") + "\n")
+    res, _ = authlua.g.auth_password_verify(request_for(USER1), "correctgoose")
+    assert res == OK
+    assert authlua.g.auth_userdb_lookup(request_for(USER1))[0] == OK
+
+    passhash = encrypt_password("correctgoose")
+    write_password_file(USER1, passhash + "\ntrailing junk")
+    authlua.g.create_status = 403
+    res, _ = authlua.g.auth_password_verify(request_for(USER1), "correctgoose")
+    assert res == UNKNOWN
+    assert authlua.g.auth_userdb_lookup(request_for(USER1))[0] == UNKNOWN
+
+
+def test_ipv4_relay_uses_bracketed_domain(lua, ipv4_config, request_for):
+    # mail_domain is "[1.3.3.7]" here, and is_ours must not read it as a pattern
+    authlua = load_authlua(lua, ipv4_config)
+    addr = f"user12345@{ipv4_config.mail_domain}"
+    ipv4_config.get_user(addr).set_password(encrypt_password("correctgoose"))
+
+    res, fields = authlua.g.auth_password_verify(request_for(addr), "correctgoose")
+    assert res == OK
+    assert fields["home"].endswith(addr)
+    assert authlua.g.auth_userdb_lookup(request_for(addr))[0] == OK
+    assert authlua.g.auth_userdb_lookup(request_for(USER1))[0] == UNKNOWN

cmdeploy/src/cmdeploy/tests/test_cmdeploy.py

@@ -39,6 +39,14 @@ class TestCmdline:
         out, err = capsys.readouterr()
         assert "deleting config file" in out.lower()
 
+    def test_dns_skip_on_ip(self, capsys, tmp_path, monkeypatch):
+        monkeypatch.delenv("CHATMAIL_INI", raising=False)
+        inipath = tmp_path / "chatmail.ini"
+        assert main(["init", "--config", str(inipath), "1.3.3.7"]) == 0
+        assert main(["dns", "--config", str(inipath)]) == 0
+        out, err = capsys.readouterr()
+        assert out == "[WARNING] 1.3.3.7 is not a domain, skipping DNS checks.\n"
+
 
 def test_www_folder(example_config, tmp_path):
     reporoot = importlib.resources.files(__package__).joinpath("../../../../").resolve()

cmdeploy/src/cmdeploy/tests/test_dovecot_deployer.py

@@ -3,30 +3,40 @@ from types import SimpleNamespace
 
 import pytest
 from pyinfra.facts.deb import DebPackages
+from pyinfra.facts.server import Command
 
 from cmdeploy.dovecot import deployer as dovecot_deployer
 
 
+def _fact_name(key):
+    if isinstance(key, tuple):
+        return f"{key[0].__name__}{key[1:]!r}"
+    return key.__name__
+
+
 def make_host(*fact_pairs):
-    """Build a mock host; get_fact(cls) dispatches to the provided facts mapping.
+    """Build a mock host; get_fact() dispatches to the provided facts mapping.
 
     Args:
-        *fact_pairs: tuples of (fact_class, fact_value) to register
+        *fact_pairs: (fact_class, value) to match any call of that fact, or
+            ((fact_class, *args), value) to match one specific call. Needed
+            for Command, which install() and check_restart() invoke with
+            different scripts; a bare Command entry would serve both.
 
     Returns:
         SimpleNamespace with get_fact that raises a clear error if an
-        unexpected fact type is requested.
+        unregistered fact is requested.
     """
     facts = dict(fact_pairs)
 
-    def get_fact(cls):
-        if cls not in facts:
-            registered = ", ".join(c.__name__ for c in facts)
-            raise LookupError(
-                f"unexpected get_fact({cls.__name__}); "
-                f"only registered: {registered}"
-            )
-        return facts[cls]
+    def get_fact(cls, *args):
+        for key in ((cls, *args), cls):
+            if key in facts:
+                return facts[key]
+        registered = ", ".join(_fact_name(k) for k in facts)
+        raise LookupError(
+            f"unexpected get_fact({_fact_name((cls, *args))}); only registered: {registered}"
+        )
 
     return SimpleNamespace(get_fact=get_fact)
 
@@ -65,7 +75,9 @@ def track_shell(monkeypatch):
 
 
 def test_download_dovecot_package_skips_epoch_matched_install(monkeypatch):
-    epoch_version = dovecot_deployer.DOVECOT_PACKAGE_VERSION
+    # what dpkg reports after installing our deb: epoch + the +debNu1 suffix
+    # that chatmail/dovecot CI stamps via dch before building
+    epoch_version = f"1:{dovecot_deployer._stamped_version(12)}"
     downloads = []
     monkeypatch.setattr(
         dovecot_deployer,
@@ -83,15 +95,17 @@ def test_download_dovecot_package_skips_epoch_matched_install(monkeypatch):
         lambda **kwargs: downloads.append(kwargs),
     )
 
-    deb, changed = dovecot_deployer._download_dovecot_package("core", "amd64")
+    deb, changed = dovecot_deployer._download_dovecot_package("core", "amd64", deb_release=12)
 
     assert deb is None, f"expected no deb path when version matches, got {deb!r}"
     assert changed is False, "should not flag changed when version already installed"
     assert downloads == [], "should not download when version already installed"
 
 
+@pytest.mark.parametrize("deb_release", [12, 13])
+@pytest.mark.parametrize("arch", ["amd64", "arm64"])
 def test_download_dovecot_package_uses_archive_version_for_url_and_filename(
-    monkeypatch,
+    monkeypatch, deb_release, arch
 ):
     downloads = []
     monkeypatch.setattr(
@@ -110,18 +124,26 @@ def test_download_dovecot_package_uses_archive_version_for_url_and_filename(
         lambda **kwargs: downloads.append(kwargs),
     )
 
-    deb, changed = dovecot_deployer._download_dovecot_package("core", "amd64")
+    deb, changed = dovecot_deployer._download_dovecot_package(
+        "core", arch, deb_release=deb_release
+    )
 
-    archive_version = dovecot_deployer.DOVECOT_ARCHIVE_VERSION.replace("+", "%2B")
-    expected_deb = f"/root/dovecot-core_{archive_version}_amd64.deb"
+    stamped = dovecot_deployer._stamped_version(deb_release)
+    expected_deb = f"/root/dovecot-core_{stamped}_{arch}.deb"
 
-    # Verify the returned path uses archive version, not package version (with epoch)
+    # path uses the stamped version, and deb filenames never carry the epoch
     assert changed is True, "should flag changed when package not yet installed"
     assert deb == expected_deb, f"deb path mismatch: {deb!r} != {expected_deb!r}"
-    assert dovecot_deployer.DOVECOT_PACKAGE_VERSION not in deb, (
-        f"deb path should use archive version (no epoch), got {deb!r}"
-    )
+    assert "1:" not in deb, f"deb filename must not contain the epoch, got {deb!r}"
     assert len(downloads) == 1, "files.download should be called exactly once"
+    # the checksum is the security boundary: verify the right table row is used
+    assert (
+        downloads[0]["sha256sum"]
+        == dovecot_deployer.DOVECOT_SHA256[(arch, deb_release, "core")]
+    ), "must pass the sha256 matching (arch, release, package)"
+    assert f"deb{deb_release}u1" in downloads[0]["src"], (
+        f"download URL should carry the deb{deb_release} suffix, got {downloads[0]['src']!r}"
+    )
 
 
 def test_install_skips_dpkg_path_when_epoch_matched_packages_present(
@@ -134,12 +156,14 @@ def test_install_skips_dpkg_path_when_epoch_matched_packages_present(
             (
                 dovecot_deployer.DebPackages,
                 {
-                    "dovecot-core": [dovecot_deployer.DOVECOT_PACKAGE_VERSION],
-                    "dovecot-imapd": [dovecot_deployer.DOVECOT_PACKAGE_VERSION],
-                    "dovecot-lmtpd": [dovecot_deployer.DOVECOT_PACKAGE_VERSION],
+                    "dovecot-core": [f"1:{dovecot_deployer._stamped_version(12)}"],
+                    "dovecot-imapd": [f"1:{dovecot_deployer._stamped_version(12)}"],
+                    "dovecot-lmtpd": [f"1:{dovecot_deployer._stamped_version(12)}"],
+                    "dovecot-auth-lua": [f"1:{dovecot_deployer._stamped_version(12)}"],
                 },
             ),
             (dovecot_deployer.Arch, "x86_64"),
+            ((Command, dovecot_deployer.VERSION_ID_CMD), 'VERSION_ID="12"'),
         ),
     )
     downloads = []
@@ -153,41 +177,26 @@ def test_install_skips_dpkg_path_when_epoch_matched_packages_present(
 
     assert downloads == [], "should not download when all packages epoch-matched"
     assert track_shell == [], "should not run dpkg when all packages epoch-matched"
-    assert deployer.need_restart is False, (
-        "need_restart should be False when nothing changed"
-    )
+    assert deployer.need_restart is False, "need_restart should be False when nothing changed"
 
 
-def test_install_unsupported_arch_falls_back_to_apt(
+def test_install_unsupported_arch_raises(
     deployer, patch_blocked, mock_files_put, track_shell, monkeypatch
 ):
-    # For unsupported architectures, all fact lookups return the arch string.
     monkeypatch.setattr(
         dovecot_deployer,
         "host",
-        SimpleNamespace(get_fact=lambda cls: "riscv64"),
+        make_host(
+            (dovecot_deployer.Arch, "riscv64"),
+            ((Command, dovecot_deployer.VERSION_ID_CMD), 'VERSION_ID="12"'),
+        ),
     )
-    apt_calls = []
 
-    # Mirrors apt.packages() return value: OperationMeta with .changed property.
-    # Only lmtpd triggers a change to verify |= accumulation of changed flags.
-    def fake_apt(**kwargs):
-        apt_calls.append(kwargs)
-        changed = "lmtpd" in kwargs["packages"][0]
-        return SimpleNamespace(changed=changed)
+    # we never fall back to the pinned distro package
+    with pytest.raises(ValueError, match="no dovecot build for dovecot-core"):
+        deployer.install()
 
-    monkeypatch.setattr(dovecot_deployer.apt, "packages", fake_apt)
-
-    deployer.install()
-
-    actual_pkgs = [c["packages"] for c in apt_calls]
-    assert actual_pkgs == [["dovecot-core"], ["dovecot-imapd"], ["dovecot-lmtpd"]], (
-        f"expected apt install of core/imapd/lmtpd, got {actual_pkgs}"
-    )
-    assert track_shell == [], "should not run dpkg for unsupported arch"
-    assert deployer.need_restart is True, (
-        "need_restart should be True when apt installed a package"
-    )
+    assert track_shell == [], "should not run apt-get for unsupported arch"
 
 
 def test_install_runs_dpkg_when_packages_need_download(
@@ -199,6 +208,7 @@ def test_install_runs_dpkg_when_packages_need_download(
         make_host(
             (dovecot_deployer.DebPackages, {}),
             (dovecot_deployer.Arch, "x86_64"),
+            ((Command, dovecot_deployer.VERSION_ID_CMD), 'VERSION_ID="12"'),
         ),
     )
     monkeypatch.setattr(
@@ -214,17 +224,15 @@ def test_install_runs_dpkg_when_packages_need_download(
 
     deployer.install()
 
-    assert len(track_shell) == 1, (
-        f"expected one server.shell() call for dpkg install, got {len(track_shell)}"
-    )
+    assert len(track_shell) == 1, f"expected one server.shell() call for dpkg install, got {len(track_shell)}"
     cmds = track_shell[0]["commands"]
-    assert len(cmds) == 3, f"expected 3 dpkg/apt commands, got: {cmds}"
-    assert cmds[0].startswith("dpkg --force-confdef --force-confold -i ")
-    assert "apt-get -y --fix-broken install" in cmds[1]
-    assert cmds[2].startswith("dpkg --force-confdef --force-confold -i ")
-    assert deployer.need_restart is True, (
-        "need_restart should be True after dpkg install"
-    )
+    assert len(cmds) == 1, f"expected single apt-get install command, got: {cmds}"
+    assert "apt-get install -y" in cmds[0]
+    assert '-o Dpkg::Options::="--force-confdef"' in cmds[0]
+    assert '-o Dpkg::Options::="--force-confold"' in cmds[0]
+    assert "--allow-downgrades" in cmds[0]
+    assert ".deb" in cmds[0]
+    assert deployer.need_restart is True, "need_restart should be True after dpkg install"
 
 
 def test_pick_url_falls_back_on_primary_error(monkeypatch):
@@ -233,6 +241,45 @@ def test_pick_url_falls_back_on_primary_error(monkeypatch):
 
     monkeypatch.setattr(dovecot_deployer.urllib.request, "urlopen", raise_error)
     result = dovecot_deployer._pick_url("http://primary", "http://fallback")
-    assert result == "http://fallback", (
-        f"should fall back when primary fails, got {result!r}"
+    assert result == "http://fallback", f"should fall back when primary fails, got {result!r}"
+
+
+def test_install_fails_on_unsupported_debian_version(deployer, patch_blocked, monkeypatch):
+    monkeypatch.setattr(
+        dovecot_deployer,
+        "host",
+        make_host(
+            (dovecot_deployer.Arch, "x86_64"),
+            ((Command, dovecot_deployer.VERSION_ID_CMD), 'VERSION_ID="99"'),
+        ),
     )
+
+    with pytest.raises(ValueError, match="no dovecot build for dovecot-core on deb99"):
+        deployer.install()
+
+
+@pytest.mark.parametrize(
+    "version_line", ["", None, "ID=debian"], ids=["empty", "none", "no-version-id"]
+)
+def test_parse_version_id_raises_without_version_id(version_line):
+    with pytest.raises(ValueError, match="cannot determine Debian release"):
+        dovecot_deployer._parse_version_id(version_line)
+
+
+@pytest.mark.parametrize("deb_release", [12, 13])
+def test_parse_version_id(deb_release):
+    parsed = dovecot_deployer._parse_version_id(f'VERSION_ID="{deb_release}"\n')
+    assert parsed == deb_release
+
+
+def test_dovecot_sha256_covers_all_packages_per_release():
+    """Every release in the table needs all four packages on both arches."""
+    table = dovecot_deployer.DOVECOT_SHA256
+    expected = {
+        (arch, pkg)
+        for arch in ("amd64", "arm64")
+        for pkg in ("core", "imapd", "lmtpd", "auth-lua")
+    }
+    for release in {r for _, r, _ in table}:
+        got = {(arch, pkg) for arch, r, pkg in table if r == release}
+        assert got == expected, f"deb{release} incomplete: {sorted(expected - got)}"

cmdeploy/src/cmdeploy/tests/test_pushlua.py

@@ -0,0 +1,85 @@
+"""Test the push_notification.lua we ship, against a mocked dovecot mail API."""
+
+import textwrap
+
+import pytest
+
+USER1 = "user12345@chat.example.org"
+USER2 = "user67890@chat.example.org"
+
+DOVECOT_MOCKS = textwrap.dedent("""
+    function make_user(username)
+      local function mailbox(_, name)
+        record("mailbox " .. name)
+        return {
+          sync = function() record("sync") end,
+          metadata_set = function(_, k, v)
+            record("metadata_set " .. k .. "=" .. v)
+          end,
+          free = function() record("free") end,
+        }
+      end
+      return {username = username, mailbox = mailbox}
+    end
+""")
+
+
+@pytest.fixture
+def script(lua):
+    lua.rt.execute(DOVECOT_MOCKS)
+    lua.load("dovecot/push_notification.lua")
+    return lua
+
+
+@pytest.fixture
+def deliver(script):
+    def deliver(recipient, sender):
+        calls = []
+        script.g.record = calls.append
+        user = script.g.make_user(recipient)
+        ctx = script.g.dovecot_lua_notify_begin_txn(user)
+        event = script.table(mailbox="INBOX", from_address=sender)
+        script.g.dovecot_lua_notify_event_message_new(ctx, event)
+        script.g.dovecot_lua_notify_end_txn(ctx, True)
+        return calls
+
+    return deliver
+
+
+def test_entry_points_have_the_names_dovecot_calls(script):
+    assert script.g.dovecot_lua_notify_begin_txn is not None
+    assert script.g.dovecot_lua_notify_event_message_new is not None
+    assert script.g.dovecot_lua_notify_end_txn is not None
+
+
+def test_begin_txn_returns_the_user_as_event_context(script):
+    user = script.g.make_user(USER1)
+    ctx = script.g.dovecot_lua_notify_begin_txn(user)
+    ctx.marker = "seen"
+    assert user.marker == "seen"
+
+
+def test_incoming_message_notifies_metadata_server(deliver):
+    assert deliver(USER1, sender=USER2) == [
+        "mailbox INBOX",
+        "sync",
+        "metadata_set /private/messagenew=",
+        "free",
+    ]
+
+
+def test_own_message_does_not_wake_the_sending_device(deliver):
+    assert deliver(USER1, sender=USER1) == [
+        "mailbox INBOX",
+        "sync",
+        "free",
+    ]
+
+
+def test_message_without_from_address_is_notified(deliver):
+    assert deliver(USER1, sender=None) == [
+        "mailbox INBOX",
+        "sync",
+        "metadata_set /private/messagenew=",
+        "free",
+    ]

cmdeploy/src/cmdeploy/unbound/unbound.conf.j2

@@ -1,4 +1,7 @@
-# Managed by cmdeploy: disable IPv6 in unbound.
+# Managed by cmdeploy
 server:
+{% if disable_ipv6 %}
   interface: 127.0.0.1
   do-ip6: no
+{% endif %}
+  cache-max-negative-ttl: 0

doc/source/conf.py

@@ -3,6 +3,8 @@
 # For the full list of built-in configuration values, see the documentation:
 # https://www.sphinx-doc.org/en/master/usage/configuration.html
 
+import os
+
 # -- Project information -----------------------------------------------------
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
 
@@ -16,12 +18,24 @@ author = 'chatmail collective'
 extensions = [
     #'sphinx.ext.autodoc',
     #'sphinx.ext.viewdoc',
+    'sphinx.ext.extlinks',
     'sphinxcontrib.mermaid',
 ]
 
 templates_path = ['_templates']
 exclude_patterns = []
 
+# Repository links go through the roles below.
+# CI sets DOC_GITHUB_REF to the head commit of a pull request,
+gh_ref = os.environ.get("DOC_GITHUB_REF", "main")
+
+extlinks = {
+    "repofile": (f"https://github.com/chatmail/relay/blob/{gh_ref}/%s", "%s"),
+    "repodir": (f"https://github.com/chatmail/relay/tree/{gh_ref}/%s", "%s"),
+}
+
+# Warn about repository links spelled out in full instead of using the roles.
+extlinks_detect_hardcoded_links = True
 
 
 # -- Options for HTML output -------------------------------------------------

doc/source/faq.rst

@@ -15,6 +15,7 @@ goes beyond what classic email servers offer:
    streaming, privacy-preserving Push Notifications for Apple, Google, and `Ubuntu Touch <https://docs.ubports.com/en/latest/appdev/guides/pushnotifications.html>`_;
 
 -  **Security Enforcement**: only strict TLS, DKIM and OpenPGP with minimized metadata accepted
+   (DKIM is not enforced on :ref:`IP-only relays <iponly>`)
 
 -  **Reliable Federation and Decentralization:** No spam or IP reputation checks, federating
    depends on established IETF standards and protocols.
@@ -47,6 +48,29 @@ Dovecot, and are configured to run unattended without much maintenance
 effort. Chatmail relays happily run on low-end hardware like a Raspberry
 Pi.
 
+.. _upgrade:
+
+How can I upgrade my chatmail relay?
+------------------------------------
+
+To upgrade to the latest ``main`` branch,
+``cd`` into your local checkout of https://github.com/chatmail/relay/
+and run the following commands:
+
+   ::
+
+       git pull origin main --rebase --autostash
+       scripts/initenv.sh
+       scripts/cmdeploy run
+
+If you don't want the latest development version,
+but a specific tagged release like `1.10.0 <https://github.com/chatmail/relay/releases/tag/1.10.0>`_,
+run ``git pull origin 1.10.0`` instead.
+
+If you made local changes for your setup,
+they will be reapplied as long as they don't conflict with the upgrade.
+If a conflict arises, ``git status`` will tell you how to resolve it.
+
 
 How trustable are chatmail relays?
 ----------------------------------

doc/source/getting_started.rst

@@ -14,8 +14,6 @@ Minimal requirements and prerequisites
 
 You will need the following:
 
--  Control over a domain through a DNS provider of your choice.
-
 -  A Debian 12 **deployment server** with reachable SMTP/SUBMISSIONS/IMAPS/HTTPS ports.
    IPv6 is encouraged if available. Chatmail relay servers only require
    1GB RAM, one CPU, and perhaps 10GB storage for a few thousand active
@@ -28,6 +26,11 @@ You will need the following:
    (An ed25519 private key is required due to an `upstream bug in
    paramiko <https://github.com/paramiko/paramiko/issues/2191>`_)
 
+-  Control over a domain through a DNS provider of your choice
+   (there is experimental support for :ref:`IP-only relays <iponly>`).
+
+
+.. _setup:
 
 Setup with ``scripts/cmdeploy``
 -------------------------------------
@@ -98,6 +101,15 @@ steps. Please substitute it with your own domain.
    configure at your DNS provider (it can take some time until they are
    public).
 
+
+
+Docker installation
+-------------------
+
+There is experimental support for running chatmail via Docker.
+A monolithic image based on the above cmdeploy method is available `through a separate repository <https://github.com/chatmail/docker/pkgs/container/docker>`_.
+See the `chatmail/docker README <https://github.com/chatmail/docker>`_ for full setup instructions.
+
 Other helpful commands
 ----------------------
 
@@ -187,6 +199,93 @@ creating addresses, login with ssh to the deployment machine and run:
 Chatmail address creation will be denied while this file is present.
 
 
+.. _system-limits:
+
+Configurable System Limits
+--------------------------
+
+Limits for auto-rejecting address creation
+..........................................
+
+A relay refuses creation of new addresses
+when the machine runs low on resources,
+but existing addresses keep working.
+
+Three ``chatmail.ini`` settings control this,
+shown here with their defaults::
+
+    max_load_1m = 5
+    min_available_memory = 200M
+    min_free_disk_space = 1G
+
+- ``max_load_1m`` is the maximum 1-minute load average,
+  as reported by ``uptime``;
+  it counts processes waiting for disk I/O as well as for CPU.
+  It is deliberately not scaled by the number of CPUs
+  because I/O rather than CPU is what typically limits a relay.
+
+- ``min_available_memory`` is the minimum memory available without swapping.
+
+- ``min_free_disk_space`` is the minimum free disk space
+  on the file system holding the mailboxes.
+
+The defaults suit the small machine described in
+`Minimal requirements and prerequisites`_.
+
+.. note::
+
+   If you run a bigger machine,
+   raise ``max_load_1m`` after watching ``uptime`` under typical load.
+
+Rejections are logged by the ``doveauth`` service,
+so you can check whether a limit is set too tightly::
+
+    journalctl -u doveauth --grep 'registration rejected'
+
+If ``mtail_address`` is set, rejections are also counted
+in the ``rejected_registrations`` metric.
+
+
+Overall IMAP and SMTP connection limits
+.......................................
+
+Two further settings bound how many connections
+the relay accepts at all, again shown with their defaults::
+
+    max_imap_connections = 10000
+    max_smtp_connections = 1000
+
+``max_imap_connections`` becomes the Dovecot imap process limit,
+and ``max_smtp_connections`` the Postfix process limit
+on each of the submission and smtps ports.
+A single client IP may use up to a fifth of ``max_smtp_connections``.
+Each connection costs memory,
+so these limits defend the relay against running out of RAM.
+
+Unless ``imap_compress`` is enabled,
+an IMAP connection that is idle for ``imap_hibernate_timeout``
+is handed over to the ``imap-hibernate`` process
+and does not count towards ``max_imap_connections``,
+which is why a relay can serve far more IMAP clients
+than this setting suggests.
+
+If you run a large relay with 10k or 100k's of addresses,
+check current connection counts before upgrading
+and set the limits accordingly.
+
+To see how close a running relay is to these two limits,
+copy ``scripts/check-connections.sh`` from the relay repository
+onto the relay and run it there::
+
+    imap             5  ports 143,993   (max_imap_connections)
+                     5  dovecot sessions, 0 of them in an active imap process
+    submission       0  ports 465,587   (max_smtp_connections per port)
+    incoming         0  port 25         (from other relays, no chatmail.ini limit)
+
+It counts established sockets with ``ss``
+and cross-checks the IMAP number against ``doveadm who``.
+
+
 Running a relay with self-signed certificates
 ----------------------------------------------
 

doc/source/index.rst

@@ -19,3 +19,4 @@ Contributions and feedback welcome through the https://github.com/chatmail/relay
     reverse_dns
     related
     faq
+    iponly

doc/source/iponly.rst

@@ -0,0 +1,40 @@
+.. _iponly:
+
+Hosting without DNS records
+===========================
+
+.. note::
+
+   This option is experimental and might change without notice.
+
+In case you don't have a domain,
+for example in a local network,
+you can run a chatmail relay with only an IPv4 address as well.
+
+To deploy a relay without a domain,
+run ``cmdeploy init`` with only the IPv4 address
+during the :ref:`installation steps <setup>`,
+for example ``cmdeploy init 13.12.23.42``.
+
+Drawbacks
+---------
+
+- your transport encryption will only use self-signed TLS certificates,
+  which are vulnerable against MITM attacks.
+  the chatmail core's end-to-end encryption should suffice in most scenarios though.
+
+- your messages will not be DKIM-signed;
+  experimentally, most chatmail relays accept non-DKIM-signed messages from IP-only relays,
+  but some relays might not accept messages from yours.
+
+
+Email addresses
+---------------
+
+When running without a domain,
+your chatmail addresses will use the IPv4 address
+in brackets as the domain part,
+for example ``user@[13.12.23.42]``.
+This is a valid email address format
+according to :rfc:`5321`.
+

doc/source/overview.rst

@@ -6,13 +6,13 @@ Technical overview
 Directories of the relay repository
 -----------------------------------
 
-The `chatmail relay repository <https://github.com/chatmail/relay/tree/main/>`_
+The `chatmail relay repository <https://github.com/chatmail/relay>`_
 has four main directories.
 
 ``scripts/``
 ~~~~~~~~~~~~~
 
-`scripts <https://github.com/chatmail/relay/tree/main/scripts>`_
+:repodir:`scripts`
 offers two convenience tools for beginners:
 
 - ``initenv.sh`` installs a local virtualenv Python environment and
@@ -71,7 +71,7 @@ The deployed system components of a chatmail relay are:
 ``chatmaild/``
 ~~~~~~~~~~~~~~
 
-`chatmaild <https://github.com/chatmail/relay/tree/main/chatmaild>`_
+:repodir:`chatmaild`
 is a Python package containing several small services which handle
 authentication, trigger push notifications on new messages, ensure
 that outbound mails are encrypted, delete inactive users, and some
@@ -83,25 +83,25 @@ that integrate with Dovecot and Postfix to achieve instant-onboarding
 and only relaying OpenPGP end-to-end messages encrypted messages. A
 short overview of ``chatmaild`` services:
 
--  `doveauth <https://github.com/chatmail/relay/blob/main/chatmaild/src/chatmaild/doveauth.py>`_
-   implements create-on-login address semantics and is used by Dovecot
-   during IMAP login and by Postfix during SMTP/SUBMISSION login which
-   in turn uses `Dovecot SASL
-   <https://doc.dovecot.org/2.3/configuration_manual/authentication/dict/#complete-example-for-authenticating-via-a-unix-socket>`_
-   to authenticate logins.
+-  :repofile:`doveauth <chatmaild/src/chatmaild/doveauth.py>`
+   implements create-on-login address semantics.
+   Dovecot authenticates IMAP logins, and Postfix SMTP/SUBMISSION logins through `Dovecot SASL
+   <https://doc.dovecot.org/2.3/configuration_manual/authentication/authentication_mechanisms/>`_,
+   from an :repofile:`auth.lua <cmdeploy/src/cmdeploy/dovecot/auth.lua.j2>` script
+   that reads the maildir directly. Only addresses which do not exist yet
+   are passed on to doveauth, which owns the creation policy.
 
--  `chatmail-metadata <https://github.com/chatmail/relay/blob/main/chatmaild/src/chatmaild/metadata.py>`_
-   is contacted by a `Dovecot lua
-   script <https://github.com/chatmail/relay/blob/main/cmdeploy/src/cmdeploy/dovecot/push_notification.lua>`_
-   to store user-specific relay-side config. On new messages, it `passes
-   the user’s push notification
-   token <https://github.com/chatmail/relay/blob/main/chatmaild/src/chatmaild/notifier.py>`_
+-  :repofile:`chatmail-metadata <chatmaild/src/chatmaild/metadata.py>`
+   is contacted by a
+   :repofile:`Dovecot lua script <cmdeploy/src/cmdeploy/dovecot/push_notification.lua>`
+   to store user-specific relay-side config. On new messages, it
+   :repofile:`passes the user’s push notification token <chatmaild/src/chatmaild/notifier.py>`
    to
    `notifications.delta.chat <https://delta.chat/en/help#instant-delivery>`_
    so the push notifications on the user’s phone can be triggered by
    Apple/Google/Huawei.
 
--  `chatmail-expire <https://github.com/chatmail/relay/blob/main/chatmaild/src/chatmaild/expire.py>`_
+-  :repofile:`chatmail-expire <chatmaild/src/chatmaild/expire.py>`
    deletes old messages, large messages, and entire mailboxes
    of users who have not logged in for longer than
    ``delete_inactive_users_after`` days.
@@ -109,15 +109,14 @@ short overview of ``chatmaild`` services:
 -  ``chatmail-quota-expire`` is called by Dovecot's ``quota_warning`` mechanism
    and will automatically remove oldest messages to keep mailboxes well under ``max_mailbox_size``.
 
--  `lastlogin <https://github.com/chatmail/relay/blob/main/chatmaild/src/chatmaild/lastlogin.py>`_
+-  :repofile:`lastlogin <chatmaild/src/chatmaild/lastlogin.py>`
    is contacted by Dovecot when a user logs in and stores the date of
    the login.
 
 ``www/``
 ~~~~~~~~~
 
-`www <https://github.com/chatmail/relay/tree/main/www>`_ contains
-the html, css, and markdown files which make up a chatmail relay’s
+:repodir:`www` contains the html, css, and markdown files which make up a chatmail relay’s
 web page. Edit them before deploying to make your chatmail relay
 stand out.
 
@@ -156,7 +155,8 @@ Chatmail relay dependency diagram
         postfix --- |10083|filtermail-transport;
         filtermail-outgoing --- |10025 reinject|postfix;
         filtermail-incoming --- |10026 reinject|postfix;
-        dovecot --- |doveauth.socket|doveauth;
+        postfix --- |milter opendkim.sock|OpenDKIM
+        dovecot --- |10084 create|doveauth;
         dovecot --- |message delivery|maildir["maildir
         /home/vmail/.../user"];
         dovecot --- |lastlogin.socket|lastlogin;
@@ -179,26 +179,51 @@ Chatmail relay dependency diagram
         style nginx-right fill:#f66;
         style postfix fill:#f66;
         style dovecot fill:#f66;
+        style OpenDKIM fill:#f66;
         style notification-proxy fill:#f66;
 
-Message between users on the same relay
----------------------------------------
+Accepting and delivering mail
+-----------------------------
 
 .. mermaid::
-    :caption: This diagram shows the path a non-federated message takes.
+    :caption: This diagram shows all the paths a message can take.
 
-    graph LR;
-        sender --> |465|smtps/smtpd;
-        sender --> |587|submission/smtpd;
-        smtps/smtpd --> |10080|filtermail;
-        submission/smtpd --> |10080|filtermail;
-        filtermail --> |10025|smtpd_reinject;
-        smtpd_reinject --> cleanup;
-        cleanup --> qmgr;
-        qmgr --> smtpd_accepts_message;
-        qmgr --> |lmtp|dovecot;
-        dovecot --> recipient;
-        dovecot --> sender's_other_devices;
+    flowchart LR
+        subgraph chatmail relay
+            subgraph postfix
+                qmgr .-> lmtp-filtermail["lmtp/lmtp-filtermail (default_transport)"]
+                qmgr .-> lmtp["lmtp (local_transport)"]
+                lmtp --> cleanup["cleanup (lmtp_header_cleanup)"]
+                bounce
+                smtpd-submission["smtpd/submission"]
+                smtpd-smtps["smtpd/smtps"]
+                smtpd-reinject-outgoing["smtpd/reinject-outgoing"] --> authclean["cleanup/authclean (submission_header_cleanup)"]
+                authclean --> qmgr
+                smtpd-smtp["smtpd/smtp"]
+                smtpd-reinject-incoming["smtpd/reinject-incoming"] --> qmgr
+            end
+            lmtp-filtermail --LMTP inet:10083--> filtermail-transport
+            cleanup --LMTP unix:private/dovecot-lmtp --> dovecot
+            dovecot --> maildir
+            smtpd-submission --SMTP inet:10080--> filtermail-outgoing
+            smtpd-smtps --SMTP inet:10080--> filtermail-outgoing
+            filtermail-outgoing --SMTP inet:10025--> smtpd-reinject-outgoing
+            open-dkim["OpenDKIM (signing only)"] <--milter unix:opendkim/opendkim.sock--> smtpd-reinject-outgoing
+            bounce <--milter unix:opendkim/opendkim.sock--> open-dkim
+            bounce --> qmgr
+            nginx
+            smtpd-smtp -.SMTP inet:10081.-> filtermail-incoming
+            nginx -.HTTP inet:10082.-> filtermail-incoming
+            filtermail-incoming --SMTP inet:10026--> smtpd-reinject-incoming
+        end
+        filtermail-transport -.SMTP inet:25.-> mta1[Remote relay]
+        filtermail-transport -.HTTPS /mxdeliv.-> mta1
+        client[Client] -.SMTP inet:587.-> smtpd-submission
+        client -.SMTP inet:465.-> smtpd-smtps
+        client -.SMTP inet:443.-> nginx
+        nginx -.SMTP inet:465.-> smtpd-smtps
+        mta2[Remote relay] -.SMTP inet:25.-> smtpd-smtp
+        mta2 -.HTTPS /mxdeliv.-> nginx
 
 Operational details of a chatmail relay
 ----------------------------------------
@@ -223,6 +248,33 @@ Fresh chatmail addresses have a mailbox directory that contains:
    directories will typically be empty unless the user of that address
    hasn’t been online for a while.
 
+App version information (experimental)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A chatmail relay ships the
+:repofile:`appversions.json <chatmaild/src/chatmaild/defaults/appversions.json>`
+file of the ``chatmaild`` package
+and serves its content under the IMAP METADATA key
+``/shared/vendor/deltachat/appversions``.
+Chat apps installed outside of app stores read this key
+to learn about updates and where to download them.
+The mechanism is experimental and may change.
+
+The file travels with the normal deploy:
+update the repository checkout and run ``cmdeploy run``.
+Local modifications of ``appversions.json`` are deployed as-is,
+so you can serve your own app version information,
+including links to app downloads.
+There is no automatic refresh:
+version information changes only when you deploy again.
+
+.. note::
+
+   Note that as of August 2026, only Delta Chat Android Google Play version
+   is beginning to support discovering app versions from relays.
+   Generally, consumers of relay-provided app version information
+   need to verify themselves that downloaded app files are valid.
+
 Active ports
 ~~~~~~~~~~~~
 
@@ -265,7 +317,8 @@ from the chatmail relay server.
 Email domain authentication (DKIM)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Chatmail relays enforce :rfc:`DKIM <6376>` to authenticate incoming emails.
+Chatmail relays enforce :rfc:`DKIM <6376>` to authenticate incoming emails
+(except for :ref:`IP-only relays <iponly>`).
 Incoming emails must have a valid DKIM signature with
 Signing Domain Identifier (SDID, ``d=`` parameter in the DKIM-Signature
 header) equal to the ``From:`` header domain. This property is checked

doc/source/related.rst

@@ -14,10 +14,11 @@ We know of three work-in-progress alternative implementation efforts:
    it to support all of the features and configuration settings required
    to operate as a chatmail relay.
 
--  `Madmail <https://github.com/themadorg/madmail>`_: an
-   experimental fork of `Maddy Mail Server <https://maddy.email/>`_, modified
-   for chatmail deployments.  It provides a single binary solution
-   for running a chatmail relay.
+-  `Madmail <https://github.com/themadorg/madmail>`_: a Rust-based
+   single-binary chatmail relay.  Madmail v2 is a rewrite of an earlier
+   experimental fork of `Maddy Mail Server <https://maddy.email/>`_.
+   It includes SMTP, IMAP, encryption enforcement, and real-time
+   services (TURN/Iroh), and runs on Linux and Windows.
 
 -  `Chatmail Cookbook <https://github.com/feld/chatmail-cookbook>`_:
    A Chef Cookbook implementing a relay server. The project follows the

scripts/check-connections.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+#
+# Show current IMAP and SMTP connections on a chatmail relay,
+# to compare against the max_imap_connections and max_smtp_connections
+# settings in chatmail.ini.  Run this on the relay itself.
+set -e
+
+# Count established TCP connections whose local port is one of the arguments.
+established() {
+    filter=$(printf 'sport = :%s or ' "$@")
+    ss -Htn state established "( ${filter% or } )" | wc -l
+}
+
+# doveadm prints a header line and then one line per logged-in user,
+# with that user's number of connections in the second column.
+sessions=$(doveadm who | awk 'NR > 1 { n += $2 } END { print n + 0 }')
+
+# Unless imap_compress is enabled, connections idle for
+# imap_hibernate_timeout are handed over to the imap-hibernate
+# process, so they cost no imap process while idle.
+active=$(pgrep -x imap | wc -l)
+
+printf 'imap        %6d  ports 143,993   (max_imap_connections)\n' "$(established 143 993)"
+printf '            %6d  dovecot sessions, %d of them in an active imap process\n' "$sessions" "$active"
+printf 'submission  %6d  ports 465,587   (max_smtp_connections per port)\n' "$(established 465 587)"
+printf 'incoming    %6d  port 25         (from other relays, no chatmail.ini limit)\n' "$(established 25)"

scripts/initenv.sh

@@ -20,6 +20,10 @@ fi
 
 python3 -m venv --upgrade-deps venv
 
+# an editable install puts src/ on sys.path, so a leftover egg-info there is
+# found as a second distribution and keeps removed entry points registered
+rm -rf chatmaild/src/*.egg-info cmdeploy/src/*.egg-info
+
 venv/bin/pip install -e chatmaild 
 venv/bin/pip install -e cmdeploy
 venv/bin/pip install sphinx sphinxcontrib-mermaid sphinx-autobuild furo  # for building the docs