fix: DNS check timeout with IPv6-broken authoritative NS

Add IPv4 fallback for authoritative NS queries in query_dns().
When dig @ns returns no useful answer (e.g. IPv6 transport to
the NS times out), retry with -4 to force IPv4. Also limits
timeout and tries (+timeout=10 +tries=2) to avoid hanging.

Fixes #851

.github/workflows/ci.yaml

@@ -9,6 +9,8 @@ on:
   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 }}
@@ -25,6 +27,7 @@ jobs:
         # Otherwise `test_deployed_state` will be unhappy.
         with:
           ref: ${{ github.event.pull_request.head.sha }}
+          persist-credentials: false
       - name: download filtermail
         run: curl -L https://github.com/chatmail/filtermail/releases/download/v0.6.1/filtermail-x86_64 -o /usr/local/bin/filtermail && chmod +x /usr/local/bin/filtermail
       - name: run chatmaild tests 
@@ -38,6 +41,7 @@ jobs:
       - uses: actions/checkout@v6
         with:
           ref: ${{ github.event.pull_request.head.sha }}
+          persist-credentials: false
 
       - name: initenv 
         run: scripts/initenv.sh

.github/workflows/docker-dispatch.yaml

@@ -0,0 +1,37 @@
+# Notify the docker repo to build and test a new image after relay CI passes.
+#
+# Sends a repository_dispatch event to chatmail/docker with the relay ref
+# and short SHA, which triggers docker-ci.yaml to build, push to GHCR,
+# and run integration tests via cmlxc.
+
+name: Trigger Docker build
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+permissions: {}
+
+jobs:
+  dispatch:
+    name: Dispatch build to chatmail/docker
+    runs-on: ubuntu-latest
+    if: github.repository == 'chatmail/relay'
+    steps:
+      - name: Compute short SHA
+        id: sha
+        run: echo "short=$(echo '${{ github.sha }}' | cut -c1-7)" >> "$GITHUB_OUTPUT"
+
+      - name: Send repository_dispatch
+        uses: peter-evans/repository-dispatch@ff45666b9427631e3450c54a1bcbee4d9ff4d7c0 # v3
+        with:
+          token: ${{ secrets.CHATMAIL_DOCKER_DISPATCH_TOKEN }}
+          repository: chatmail/docker
+          event-type: relay-updated
+          client-payload: >-
+            {
+              "relay_ref": "${{ github.ref_name }}",
+              "relay_sha": "${{ github.sha }}",
+              "relay_sha_short": "${{ steps.sha.outputs.short }}"
+            }

.github/workflows/docs-preview.yaml

@@ -7,6 +7,8 @@ on:
       - 'scripts/build-docs.sh'
       - '.github/workflows/docs-preview.yaml'
 
+permissions: {}
+
 jobs:
   scripts:
     name: build 
@@ -16,6 +18,8 @@ jobs:
       url: https://staging.chatmail.at/doc/relay/${{ steps.prepare.outputs.prid }}
     steps:
       - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
 
       - name: initenv 
         run: scripts/initenv.sh
@@ -34,18 +38,22 @@ jobs:
       - name: Get Pullrequest ID
         id: prepare
         run: |
-          export PULLREQUEST_ID=$(echo "${{ github.ref }}" | cut -d "/" -f3)
+          export PULLREQUEST_ID=$(echo "${GITHUB_REF}" | cut -d "/" -f3)
           echo "prid=$PULLREQUEST_ID" >> $GITHUB_OUTPUT
           if [ $(expr length "${{ secrets.USERNAME }}") -gt "1" ]; then echo "uploadtoserver=true" >> $GITHUB_OUTPUT; fi
       - run: |
-          echo "baseurl: /${{ steps.prepare.outputs.prid }}" >> _config.yml
+          echo "baseurl: /${STEPS_PREPARE_OUTPUTS_PRID}" >> _config.yml
+        env:
+          STEPS_PREPARE_OUTPUTS_PRID: ${{ steps.prepare.outputs.prid }}
 
       - name: Upload preview
         run: |
           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:/var/www/html/staging.chatmail.at/doc/relay/${STEPS_PREPARE_OUTPUTS_PRID}/"
+        env:
+          STEPS_PREPARE_OUTPUTS_PRID: ${{ steps.prepare.outputs.prid }}
 
       - name: check links 
         working-directory: doc

.github/workflows/docs.yaml

@@ -10,6 +10,8 @@ on:
       - 'scripts/build-docs.sh'
       - '.github/workflows/docs.yaml'
 
+permissions: {}
+
 jobs:
   scripts:
     name: build 
@@ -19,6 +21,8 @@ jobs:
       url: https://chatmail.at/doc/relay/
     steps:
       - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
 
       - name: initenv 
         run: scripts/initenv.sh

.github/workflows/zizmor-scan.yml

@@ -0,0 +1,26 @@
+name: GitHub Actions Security Analysis with zizmor
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["**"]
+
+permissions: {}
+
+jobs:
+  zizmor:
+    name: Run zizmor
+    runs-on: ubuntu-latest
+    permissions:
+      security-events: write # Required for upload-sarif (used by zizmor-action) to upload SARIF files.
+      contents: read
+      actions: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+
+      - name: Run zizmor
+        uses: zizmorcore/zizmor-action@b1d7e1fb5de872772f31590499237e7cce841e8e # v0.5.3

.github/zizmor.yml

@@ -0,0 +1,7 @@
+rules:
+  unpinned-uses:
+    config:
+      policies:
+        actions/*: ref-pin
+        dependabot/*: ref-pin
+        chatmail/*: ref-pin

CHANGELOG.md

@@ -1,5 +1,89 @@
 # Changelog for chatmail deployment 
 
+## 1.10.0 2026-04-30
+
+* start mtail after networking is fully up <https://github.com/chatmail/relay/pull/942>
+* support specifying custom filtermail binary through environment variable <https://github.com/chatmail/relay/pull/941>
+* add automated zizmor scanning of github workflows <https://github.com/chatmail/relay/pull/938>
+* added dispatch for *automated builds of chatmail relay docker images* <https://github.com/chatmail/relay/pull/934>
+* do not bind SMTP client sockets to public addresses <https://github.com/chatmail/relay/pull/932>
+* underline in docs that scripts/initenv.sh should be used for building the docs <https://github.com/chatmail/relay/pull/933>
+* automatic oldest-first message removal from mailboxes to always stay under max_mailbox_size <https://github.com/chatmail/relay/pull/929>
+* remove --slow from cmdeploy test <https://github.com/chatmail/relay/pull/931>
+* handle missing inotify sysctl keys in containers <https://github.com/chatmail/relay/pull/930>
+* replace resolvconf with static resolv.conf <https://github.com/chatmail/relay/pull/928>
+* disable fsync for LMTP and IMAP services <https://github.com/chatmail/relay/pull/925>
+* re-use cmlxc workflow, replacing CI with hetzner staging servers with local lxc containers <https://github.com/chatmail/relay/pull/917>
+* explicitly install resolvconf <https://github.com/chatmail/relay/pull/924>
+* detect stale dovecot binary and force restart in activate() <https://github.com/chatmail/relay/pull/922>
+* Rename filtermail_http_port to filtermail_http_port_incoming <https://github.com/chatmail/relay/pull/921>
+* consolidated is_in_container() check https://github.com/chatmail/relay/pull/920>
+* restart dovecot after package replacement (rebase, test condense) <https://github.com/chatmail/relay/pull/913>
+* Set permissions on dovecot pin prefs <https://github.com/chatmail/relay/pull/915>
+* Route `/mxdeliv/` to configurable port <https://github.com/chatmail/relay/pull/901>
+* fix VM detection, automated testing fixes, use newer chatmail-turn and move to standard BIND DNS zone format <https://github.com/chatmail/relay/pull/912>
+* Upgrade to filtermail 0.6.1 <https://github.com/chatmail/relay/pull/910>
+* pin dovecot packages to prevent apt upgrades <https://github.com/chatmail/relay/pull/908>
+* add rpc server to cmdeploy along with client <https://github.com/chatmail/relay/pull/906>
+* remove unused deps from chatmaild <https://github.com/chatmail/relay/pull/905>
+* set default smtp_tls_security_level to "verify" unconditionally <https://github.com/chatmail/relay/pull/902>
+* featprefer IPv4 in SMTP client <https://github.com/chatmail/relay/pull/900>
+* Install dovecot .deb packages atomically <https://github.com/chatmail/relay/pull/899>
+* stop installing cron package <https://github.com/chatmail/relay/pull/898>
+* Rewrite dovecot install logic, update <https://github.com/chatmail/relay/pull/862>
+* fix a test and some linting fixes <https://github.com/chatmail/relay/pull/897>
+* Disable IP verification on domain-literal addresses <https://github.com/chatmail/relay/pull/895>
+* disable installing recommended packages globally on the relay <https://github.com/chatmail/relay/pull/887>
+* multiple bug fixes across chatmaild and cmdeploy <https://github.com/chatmail/relay/pull/883>
+* remove /metrics from the website <https://github.com/chatmail/relay/pull/703>
+* add Prometheus textfile output to fsreport <https://github.com/chatmail/relay/pull/881>
+* chown opendkim: private key <https://github.com/chatmail/relay/pull/879>
+* make sure chatmail-metadata was started <https://github.com/chatmail/relay/pull/882>
+* dovecot update url <https://github.com/chatmail/relay/pull/880>
+* upgrade to filtermail v0.5.2 <https://github.com/chatmail/relay/pull/876>
+* download dovecot packages from github release <https://github.com/chatmail/relay/pull/875>
+* replace DKIM verification with filtermail v0.5 <https://github.com/chatmail/relay/pull/831>
+* remove CFFI deltachat bindings usage, and consolidate test support with rpc-bindings <https://github.com/chatmail/relay/pull/872>
+* prepare chatmaild/cmdeploy changes for Docker support <https://github.com/chatmail/relay/pull/857>
+* stabilize online benchmark timing adding rate-limit-aware cooldown between iterations <https://github.com/chatmail/relay/pull/867>
+* move rate-limit cooldown to benchmark fixture <https://github.com/chatmail/relay/pull/868>
+* reconfigure acmetool from redirector to proxy mode <https://github.com/chatmail/relay/pull/861>
+* make tests work with `--ssh-host localhost` <https://github.com/chatmail/relay/pull/856>
+* mark f-string with f prefix in test_expunged <https://github.com/chatmail/relay/pull/863>
+* install also if dovecot.service=False in SystemdEnabled Fact <https://github.com/chatmail/relay/pull/841>
+* Introduce support for self-signed chatmail relays <https://github.com/chatmail/relay/pull/855>
+* Strip Received headers before delivery <https://github.com/chatmail/relay/pull/849>
+* upgrade to filtermail v0.3 <https://github.com/chatmail/relay/pull/850>
+* fix link to Maddy and update madmail URL <https://github.com/chatmail/relay/pull/847>
+* accept self-signed certificates for IP-only relays <https://github.com/chatmail/relay/pull/846>
+* enforce sending from public IP addresses <https://github.com/chatmail/relay/pull/845>
+* port check: check addresses, fix single services <https://github.com/chatmail/relay/pull/844>
+* remediates issue with improper concat on resolver injection <https://github.com/chatmail/relay/pull/834>
+* ipv6 boolean not being respected during operations <https://github.com/chatmail/relay/pull/832>
+* upgrade to filtermail v0.2 by <https://github.com/chatmail/relay/pull/825>
+* fix link to filtermail <https://github.com/chatmail/relay/pull/824>
+* print timestamps when sending messages <https://github.com/chatmail/relay/pull/823>
+* fix flaky test_exceed_rate_limit <https://github.com/chatmail/relay/pull/822>
+* Replace filtermail with rust reimplementation <https://github.com/chatmail/relay/pull/808>
+* Set default internal SMTP ports in Config <https://github.com/chatmail/relay/pull/819>
+* separate metrics for incoming and outgoing messages <https://github.com/chatmail/relay/pull/820>
+* disable appending the Received header <https://github.com/chatmail/relay/pull/815>
+* fail on errors in postfix/dovecot config <https://github.com/chatmail/relay/pull/813>
+* tweak idle/hibernate metrics some more <https://github.com/chatmail/relay/pull/811>
+* add config flag to export statistics <https://github.com/chatmail/relay/pull/806>
+* add --website-only option to run subcommand <https://github.com/chatmail/relay/pull/768>
+* Strip DKIM-Signature header before LMTP <https://github.com/chatmail/relay/pull/803>
+* properly make sure that postfix gets restarted on failure <https://github.com/chatmail/relay/pull/802>
+* expire.py: use absolute path to maildirsize <https://github.com/chatmail/relay/pull/807>
+* pin Dovecot documentation URLs to version 2.3 <https://github.com/chatmail/relay/pull/800>
+* try to use "build machine" and "deployment server"  consistently  <https://github.com/chatmail/relay/pull/797>
+* adds instructions for migrating control machines <https://github.com/chatmail/relay/pull/795>
+* use consistent naming schema in getting started <https://github.com/chatmail/relay/pull/793>
+* remove jsok/serialize-workflow-action dependency <https://github.com/chatmail/relay/pull/790>
+* streamline migration guide wording, provide titled steps  <https://github.com/chatmail/relay/pull/789>
+* increases default max mailbox size <https://github.com/chatmail/relay/pull/792>
+* use daemon_name for OpenDKIM sign-verify decision instead of IP <https://github.com/chatmail/relay/pull/784>
+
 ## 1.9.0 2025-12-18
 
 ### Documentation

chatmaild/pyproject.toml

@@ -21,7 +21,8 @@ where = ['src']
 [project.scripts]
 doveauth = "chatmaild.doveauth:main"
 chatmail-metadata = "chatmaild.metadata:main"
-chatmail-expire = "chatmaild.expire:main"
+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"

chatmaild/src/chatmaild/config.py

@@ -1,4 +1,3 @@
-import os
 from pathlib import Path
 
 import iniconfig
@@ -47,8 +46,6 @@ class Config:
         )
         self.mtail_address = params.get("mtail_address")
         self.disable_ipv6 = params.get("disable_ipv6", "false").lower() == "true"
-        self.addr_v4 = os.environ.get("CHATMAIL_ADDR_V4", "")
-        self.addr_v6 = os.environ.get("CHATMAIL_ADDR_V6", "")
         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"
@@ -95,6 +92,11 @@ class Config:
         # old unused option (except for first migration from sqlite to maildir store)
         self.passdb_path = Path(params.get("passdb_path", "/home/vmail/passdb.sqlite"))
 
+    @property
+    def max_mailbox_size_mb(self):
+        """Return max_mailbox_size as an integer in megabytes."""
+        return parse_size_mb(self.max_mailbox_size)
+
     def _getbytefile(self):
         return open(self._inipath, "rb")
 
@@ -108,6 +110,16 @@ class Config:
         return User(maildir, addr, password_path, uid="vmail", gid="vmail")
 
 
+def parse_size_mb(limit):
+    """Parse a size string like ``500M`` or ``2G`` and return megabytes."""
+    value = limit.strip().upper().removesuffix("B")
+    if value.endswith("G"):
+        return int(value[:-1]) * 1024
+    if value.endswith("M"):
+        return int(value[:-1])
+    return int(value)
+
+
 def write_initial_config(inipath, mail_domain, overrides):
     """Write out default config file, using the specified config value overrides."""
     content = get_default_config_content(mail_domain, **overrides)

chatmaild/src/chatmaild/expire.py

@@ -4,17 +4,26 @@ Expire old messages and addresses.
 """
 
 import os
+import re
 import shutil
 import sys
 import time
 from argparse import ArgumentParser
 from collections import namedtuple
 from datetime import datetime
+from pathlib import Path
 from stat import S_ISREG
 
 from chatmaild.config import read_config
 
 FileEntry = namedtuple("FileEntry", ("path", "mtime", "size"))
+QuotaFileEntry = namedtuple("QuotaFileEntry", ("mtime", "quota_size", "path"))
+
+# Quota cleanup factor of max_mailbox_size. The mailbox is reset to this size.
+QUOTA_CLEANUP_FACTOR = 0.7
+
+# e.g. "cur/1775324677.M448978P3029757.exam,S=3235,W=3305:2,S"
+_dovecot_fn_rex = re.compile(r".+/(\d+)\..+,S=(\d+)")
 
 
 def iter_mailboxes(basedir, maxnum):
@@ -74,6 +83,42 @@ class MailboxStat:
         self.extrafiles.sort(key=lambda x: -x.size)
 
 
+def parse_dovecot_filename(relpath):
+    m = _dovecot_fn_rex.match(relpath)
+    if not m:
+        return None
+    return QuotaFileEntry(int(m.group(1)), int(m.group(2)), relpath)
+
+
+def scan_mailbox_messages(mbox):
+    messages = []
+    for sub in ("cur", "new"):
+        for name in os_listdir_if_exists(mbox / sub):
+            if entry := parse_dovecot_filename(f"{sub}/{name}"):
+                messages.append(entry)
+    return messages
+
+
+def expire_to_target(mbox, target_bytes):
+    messages = scan_mailbox_messages(mbox)
+    total_size = sum(m.quota_size for m in messages)
+    # Keep recent 24 hours of messages protected from expiry because
+    # likely something is wrong with interactions on that address
+    # and quota-full signal can help the address owner's device to notice it
+    undeletable_messages_cutoff = time.time() - (3600 * 24)
+    removed = 0
+    for entry in sorted(messages):
+        if total_size <= target_bytes:
+            break
+        if entry.mtime > undeletable_messages_cutoff:
+            break
+        (mbox / entry.path).unlink(missing_ok=True)
+        total_size -= entry.quota_size
+        removed += 1
+
+    return removed
+
+
 def print_info(msg):
     print(msg, file=sys.stderr)
 
@@ -143,6 +188,19 @@ class Expiry:
             else:
                 continue
             changed = True
+
+        target_bytes = (
+            self.config.max_mailbox_size_mb * 1024 * 1024 * QUOTA_CLEANUP_FACTOR
+        )
+        removed = expire_to_target(Path(mbox.basedir), target_bytes)
+        if removed:
+            changed = True
+            self.del_files += removed
+            if self.verbose:
+                print_info(
+                    f"quota-expire: removed {removed} message(s) from {mboxname}"
+                )
+
         if changed:
             self.remove_file(f"{mbox.basedir}/maildirsize")
 
@@ -154,9 +212,9 @@ class Expiry:
         )
 
 
-def main(args=None):
+def daily_expire_main(args=None):
     """Expire mailboxes and messages according to chatmail config"""
-    parser = ArgumentParser(description=main.__doc__)
+    parser = ArgumentParser(description=daily_expire_main.__doc__)
     ini = "/usr/local/lib/chatmaild/chatmail.ini"
     parser.add_argument(
         "chatmail_ini",
@@ -202,5 +260,33 @@ def main(args=None):
     print(exp.get_summary())
 
 
-if __name__ == "__main__":
-    main(sys.argv[1:])
+def quota_expire_main(args=None):
+    """Remove mailbox messages to stay within a megabyte target.
+
+    This entry point is called by dovecot when a quota threshold is passed.
+    """
+
+    parser = ArgumentParser(description=quota_expire_main.__doc__)
+    parser.add_argument(
+        "target_mb",
+        type=int,
+        help="target mailbox size in megabytes",
+    )
+    parser.add_argument(
+        "mailbox_path",
+        type=Path,
+        help="path to a user mailbox",
+    )
+    args = parser.parse_args(args)
+
+    target_bytes = args.target_mb * 1024 * 1024
+
+    removed_count = expire_to_target(args.mailbox_path, target_bytes)
+    if removed_count:
+        (args.mailbox_path / "maildirsize").unlink(missing_ok=True)
+        print(
+            f"quota-expire: removed {removed_count} message(s)"
+            f" from {args.mailbox_path.name}",
+            file=sys.stderr,
+        )
+    return 0

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

@@ -18,6 +18,7 @@ max_user_send_per_minute = 60
 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
 
 # maximum message size for an e-mail in bytes

chatmaild/src/chatmaild/tests/test_config.py

@@ -1,6 +1,6 @@
 import pytest
 
-from chatmaild.config import read_config
+from chatmaild.config import parse_size_mb, read_config
 
 
 def test_read_config_basic(example_config):
@@ -121,3 +121,17 @@ def test_config_tls_external_bad_format(make_config):
                 "tls_external_cert_and_key": "/only/one/path.pem",
             },
         )
+
+
+def test_parse_size_mb():
+    assert parse_size_mb("500M") == 500
+    assert parse_size_mb("2G") == 2048
+    assert parse_size_mb("  1g  ") == 1024
+    assert parse_size_mb("100MB") == 100
+    assert parse_size_mb("256") == 256
+
+
+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

chatmaild/src/chatmaild/tests/test_delete_inactive_users.py

@@ -1,7 +1,7 @@
 import time
 
 from chatmaild.doveauth import AuthDictProxy
-from chatmaild.expire import main as main_expire
+from chatmaild.expire import daily_expire_main as main_expire
 
 
 def test_login_timestamps(example_config):

chatmaild/src/chatmaild/tests/test_expire.py

@@ -1,5 +1,7 @@
+import itertools
 import os
 import random
+import time
 from datetime import datetime
 from fnmatch import fnmatch
 from pathlib import Path
@@ -9,13 +11,19 @@ import pytest
 from chatmaild.expire import (
     FileEntry,
     MailboxStat,
+    expire_to_target,
     get_file_entry,
     iter_mailboxes,
     os_listdir_if_exists,
+    parse_dovecot_filename,
+    quota_expire_main,
+    scan_mailbox_messages,
 )
-from chatmaild.expire import main as expiry_main
+from chatmaild.expire import daily_expire_main as expiry_main
 from chatmaild.fsreport import main as report_main
 
+MB = 1024 * 1024
+
 
 def fill_mbox(folderdir):
     password = folderdir.joinpath("password")
@@ -196,3 +204,51 @@ def test_os_listdir_if_exists(tmp_path):
     tmp_path.joinpath("x").write_text("hello")
     assert len(os_listdir_if_exists(str(tmp_path))) == 1
     assert len(os_listdir_if_exists(str(tmp_path.joinpath("123123")))) == 0
+
+
+# --- quota expire tests ---
+
+_msg_counter = itertools.count(1)
+
+
+def _create_message(basedir, sub, size, days_old=0, disk_size=None):
+    seq = next(_msg_counter)
+    mtime = int(time.time() - days_old * 86400)
+    name = f"{mtime}.M1P1Q{seq}.hostname,S={size},W={size}:2,S"
+    path = basedir / sub / name
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_bytes(b"x" * (disk_size if disk_size is not None else size))
+    os.utime(path, (mtime, mtime))
+    return path
+
+
+def test_parse_dovecot_filename():
+    e = parse_dovecot_filename("cur/1775324677.M448978P3029757.exam,S=3235,W=3305:2,S")
+    assert e.path == "cur/1775324677.M448978P3029757.exam,S=3235,W=3305:2,S"
+    assert e.mtime == 1775324677
+    assert e.quota_size == 3235
+    assert parse_dovecot_filename("cur/msg_without_structure") is None
+
+
+def test_expire_to_target(tmp_path):
+    _create_message(tmp_path, "cur", MB, days_old=10, disk_size=100)
+    _create_message(tmp_path, "new", MB, days_old=5)
+    _create_message(tmp_path, "cur", MB, days_old=0)  # undeletable (<1 hour)
+    assert len(scan_mailbox_messages(tmp_path)) == 3
+    # removes oldest first, uses S= size not disk size
+    removed = expire_to_target(tmp_path, MB)
+    assert removed == 2
+    msgs = scan_mailbox_messages(tmp_path)
+    assert len(msgs) == 1
+    # the surviving message is the fresh undeletable one
+    assert msgs[0].mtime > time.time() - 3600
+
+
+def test_quota_expire_main(tmp_path, capsys):
+    mbox = tmp_path / "user@example.org"
+    _create_message(mbox, "cur", 2 * MB, days_old=5)
+    (mbox / "maildirsize").write_text("x")
+    quota_expire_main([str(1), str(mbox)])
+    _, err = capsys.readouterr()
+    assert "quota-expire: removed 1 message(s) from user@example.org" in err
+    assert not (mbox / "maildirsize").exists()

cmdeploy/src/cmdeploy/cmdeploy.py

@@ -101,9 +101,6 @@ def run_cmd(args, out):
     env["CHATMAIL_WEBSITE_ONLY"] = "True" if args.website_only else ""
     env["CHATMAIL_DISABLE_MAIL"] = "True" if args.disable_mail else ""
     env["CHATMAIL_REQUIRE_IROH"] = "True" if require_iroh else ""
-    if not args.dns_check_disabled:
-        env["CHATMAIL_ADDR_V4"] = remote_data.get("A") or ""
-        env["CHATMAIL_ADDR_V6"] = remote_data.get("AAAA") or ""
     deploy_path = importlib.resources.files(__package__).joinpath("run.py").resolve()
     pyinf = "pyinfra --dry" if args.dry_run else "pyinfra"
 

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

@@ -149,12 +149,26 @@ plugin {
 }
 
 plugin {
-  # for now we define static quota-rules for all users 
   quota = maildir:User quota
-  quota_rule = *:storage={{ config.max_mailbox_size }}
   quota_max_mail_size={{ config.max_message_size }}
   quota_grace = 0
-  # quota_over_flag_value = TRUE
+
+  quota_rule = *:storage={{ config.max_mailbox_size_mb }}M
+
+  # Trigger at 75%% of quota, expire oldest messages down to 70%%.
+  # The percentages are chosen to prevent current Delta Chat users
+  # from seeing "quota warnings" which trigger at 80% and 95%.
+
+  quota_warning = storage=75%% quota-warning {{ config.max_mailbox_size_mb * 70 // 100 }} {{ config.mailboxes_dir }}/%u
+}
+
+service quota-warning {
+  executable = script /usr/local/lib/chatmaild/venv/bin/chatmail-quota-expire
+  user = vmail
+  unix_listener quota-warning {
+     user = vmail
+     mode = 0600
+  }
 }
 
 # push_notification configuration

cmdeploy/src/cmdeploy/filtermail/deployer.py

@@ -1,3 +1,5 @@
+import os
+
 from pyinfra import facts, host
 from pyinfra.operations import files, systemd
 
@@ -13,6 +15,16 @@ class FiltermailDeployer(Deployer):
         self.need_restart = False
 
     def install(self):
+        local_bin = os.environ.get("CHATMAIL_FILTERMAIL_BINARY")
+        if local_bin:
+            self.need_restart |= files.put(
+                name="Upload locally built filtermail",
+                src=local_bin,
+                dest=self.bin_path,
+                mode="755",
+            ).changed
+            return
+
         arch = host.get_fact(facts.server.Arch)
         url = f"https://github.com/chatmail/filtermail/releases/download/v0.6.1/filtermail-{arch}"
         sha256sum = {

cmdeploy/src/cmdeploy/mtail/delivered_mail.mtail

@@ -78,3 +78,11 @@ counter rejected_unencrypted_mail_count
 /Rejected unencrypted mail/ {
   rejected_unencrypted_mail_count++
 }
+
+counter quota_expire_runs
+counter quota_expire_removed_files
+
+/quota-expire: removed (?P<count>\d+) message\(s\)/ {
+  quota_expire_runs++
+  quota_expire_removed_files += $count
+}

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

@@ -1,5 +1,6 @@
 [Unit]
 Description=mtail
+After=multi-user.target
 
 [Service]
 Type=simple

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

@@ -69,15 +69,6 @@ mynetworks = 127.0.0.0/8
 {% else %}
 mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
 {% endif %}
-{% if config.addr_v4 %}
-smtp_bind_address = {{ config.addr_v4 }}
-{% endif %}
-{% if config.addr_v6 %}
-smtp_bind_address6 = {{ config.addr_v6 }}
-{% endif %}
-{% if config.addr_v4 or config.addr_v6 %}
-smtp_bind_address_enforce = yes
-{% endif %}
 mailbox_size_limit = 0
 message_size_limit = {{config.max_message_size}}
 recipient_delimiter = +

cmdeploy/src/cmdeploy/remote/rdns.py

@@ -64,11 +64,13 @@ def get_dkim_entry(mail_domain, pre_command, dkim_selector):
     )
 
 
-def query_dns(typ, domain):
+def query_dns(typ, domain, shell_exec=None):
+    if shell_exec is None:
+        shell_exec = shell
     # Get autoritative nameserver from the SOA record.
     soa_answers = [
         x.split()
-        for x in shell(
+        for x in shell_exec(
             f"dig -r -q {domain} -t SOA +noall +authority +answer", print=log_progress
         ).split("\n")
     ]
@@ -78,8 +80,27 @@ def query_dns(typ, domain):
     ns = soa[0][4]
 
     # Query authoritative nameserver directly to bypass DNS cache.
-    res = shell(f"dig @{ns} -r -q {domain} -t {typ} +short", print=log_progress)
-    return next((line for line in res.split("\n") if not line.startswith(";")), "")
+    return _dig_authoritative(ns, domain, typ, shell_exec=shell_exec)
+
+
+def _parse_dig_result(output):
+    """Return first non-comment, non-empty line from dig output, or empty string."""
+    lines = [line for line in output.split("\n") if not line.startswith(";")]
+    return next((line for line in lines if line.strip()), "")
+
+
+def _dig_authoritative(ns, domain, typ, shell_exec=None):
+    """Query authoritative NS, falling back to IPv4-only if default fails."""
+    if shell_exec is None:
+        shell_exec = shell
+
+    # limit timeout and tries to not hang on a broken default NS
+    cmd = f"dig @{ns} -r -q {domain} -t {typ} +short +timeout=10 +tries=2"
+    result = _parse_dig_result(shell_exec(cmd, print=log_progress))
+    if result:
+        return result
+    # Fallback: force IPv4 transport (handles broken IPv6 to NS)
+    return _parse_dig_result(shell_exec(cmd + " -4", print=log_progress))
 
 
 def check_zonefile(zonefile, verbose=True):

cmdeploy/src/cmdeploy/tests/test_dns.py

@@ -214,3 +214,59 @@ class TestZonefileChecks:
         assert not mockout.captured_red
         assert "correct" in mockout.captured_green[0]
         assert not mockout.captured_red
+
+
+class TestDigAuthoritative:
+    @pytest.fixture
+    def dig_auth(self):
+        """Helper that calls _dig_authoritative with a recording shell function."""
+        calls = []
+
+        def run(first_result, ipv4_result=None):
+            def shell(cmd, print=print):
+                calls.append(cmd)
+                if "-4" in cmd:
+                    return ipv4_result or ""
+                return first_result
+
+            result = remote.rdns._dig_authoritative(
+                "ns1.example.", "example.com", "A", shell_exec=shell
+            )
+            return result, calls
+
+        return run
+
+    def test_ipv4_fallback_on_error(self, dig_auth):
+        """Fallback to -4 when first query returns only error lines."""
+        result, calls = dig_auth(
+            first_result=(
+                ";; communications error to 2a01:4f8:10a:1044::80#53: timed out\n"
+                ";; communications error to 2a01:4f8:10a:1044::80#53: timed out\n"
+            ),
+            ipv4_result="1.2.3.4",
+        )
+        assert len(calls) == 2
+        assert "-4" not in calls[0]
+        assert "-4" in calls[1]
+        assert result == "1.2.3.4"
+
+    def test_no_fallback_on_success(self, dig_auth):
+        """No -4 fallback when first query returns a valid answer."""
+        result, calls = dig_auth(first_result="1.2.3.4")
+        assert result == "1.2.3.4"
+        assert len(calls) == 1
+
+    def test_fallback_with_mixed_error_lines(self, dig_auth):
+        """Fallback triggers when output has only error lines mixed with empty."""
+        result, calls = dig_auth(
+            first_result=(
+                ";; communications error to 2a01:4f8::80#53: timed out\n"
+                "\n"
+                ";; communications error to 2a01:4f8::80#53: timed out\n"
+            ),
+            ipv4_result=";; some warning\n1.2.3.4",
+        )
+        assert len(calls) == 2
+        assert result == "1.2.3.4"
+
+

doc/README.md

@@ -4,12 +4,14 @@
 
 You can use the `make` command and `make html` to build web pages. 
 
-You need a Python environment where the following install was excuted: 
-
-    pip install furo sphinx-autobuild
+You need a Python environment with `sphinx` and other
+dependencies, you can create it by running `scripts/initenv.sh`
+from the repository root.
 
 To develop/change documentation, you can then do: 
 
+    . venv/bin/activate
+    cd doc
     make auto 
 
 A page will open at https://127.0.0.1:8000/ serving the docs and it will 

doc/source/index.rst

@@ -16,5 +16,6 @@ Contributions and feedback welcome through the https://github.com/chatmail/relay
     proxy
     migrate
     overview
+    reverse_dns
     related
     faq

doc/source/overview.rst

@@ -102,8 +102,12 @@ short overview of ``chatmaild`` services:
    Apple/Google/Huawei.
 
 -  `chatmail-expire <https://github.com/chatmail/relay/blob/main/chatmaild/src/chatmaild/expire.py>`_
-   deletes users if they have not logged in for a longer while.
-   The timeframe can be configured in ``chatmail.ini``.
+   deletes old messages, large messages, and entire mailboxes
+   of users who have not logged in for longer than
+   ``delete_inactive_users_after`` days.
+
+-  ``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>`_
    is contacted by Dovecot when a user logs in and stores the date of
@@ -156,6 +160,8 @@ Chatmail relay dependency diagram
         /home/vmail/.../user"];
         dovecot --- |lastlogin.socket|lastlogin;
         dovecot --- chatmail-metadata;
+        dovecot --- |quota-warning|chatmail-quota-expire;
+        chatmail-quota-expire --- maildir;
         lastlogin --- maildir;
         doveauth --- maildir;
         chatmail-expire-daily --- maildir;

doc/source/reverse_dns.rst

@@ -0,0 +1,64 @@
+Configuring reverse DNS
+=======================
+
+Some email servers reject the emails
+if they don't pass `FCrDNS`_ check, also known as `iprev`_ check.
+
+.. _FCrDNS: https://en.wikipedia.org/wiki/Forward-confirmed_reverse_DNS
+.. _iprev: https://datatracker.ietf.org/doc/html/rfc8601#section-3
+
+Passing the check requires that the IP address that email is sent from
+should have a ``PTR`` record pointing to the domain name of the server,
+and domain name record should have an ``A/AAAA`` record
+pointing to the IP address.
+
+Modern email relies on DKIM and SPF for authentication,
+while iprev check exists for
+`historical reasons <https://datatracker.ietf.org/doc/html/draft-ietf-dnsop-reverse-mapping-considerations-06#section-2.1>`_.
+Chatmail relays don't resolve ``PTR`` records,
+so you can ignore this section if configuring ``PTR`` records
+is difficult and federation with legacy email servers that don't accept
+valid DKIM signature for authentication is not important.
+
+Multi-homed setups
+------------------
+
+If you have a server with multiple IP addresses,
+also known as multi-homed setup,
+and don't publish all IP addresses in DNS,
+you need to make sure you are using
+the published address when making outgoing connections.
+
+For example, your server may have a static IP
+address, and a so-called Floating IP or Virtual IP
+that can be moved between servers in case of
+migration or for failover.
+By using Floating IP you can avoid downtime
+and keep the IP address reputation
+for destinatinons that rely on IP reputation and IP blocklists.
+In this case you will only publish
+the Floating IP to DNS and only use the static IP
+to SSH into the server.
+
+If you have such setup, make sure that
+you not only set ``PTR`` records for the Floating IP,
+but make outgoing connections using the Floating IP.
+Otherwise reverse DNS check succeed,
+but forward check making sure your domain name points
+to the IP address will fail.
+Such setup is indistinguishable from someone
+setting IP address ``PTR`` with the domain they don't own
+and as a result don't succeed.
+
+On Linux you can configure source IP address with ``ip route`` command,
+for example:
+::
+
+  ip route change default via <default-gateway> dev eth0 src <source-address>
+
+Make sure to persist the change after verifying it is working.
+You can check what your outgoing IP address is
+with ``curl icanhazip.com``.
+Check both the IPv4 and IPv6 addresses.
+For IPv4 address use ``curl ipv4.icanhazip.com`` or ``curl -4 icanhazip.com``
+and similarly for IPv6 if you have it.