feat: add tool to analyze deferred queue

It prints all destinations with the number of recipients
and all the reasons. Operator can then try
to fix the problems for destinations,
e.g. by manually adding reverse proxy
addresses to /etc/hosts for failing domains
or routing IP addresses to another interface.

.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 }}
@@ -25,8 +27,9 @@ 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
+        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
       - name: run chatmaild tests 
         working-directory: chatmaild
         run: pipx run tox
@@ -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

@@ -24,6 +24,7 @@ chatmail-metadata = "chatmaild.metadata:main"
 chatmail-expire = "chatmaild.expire:daily_expire_main"
 chatmail-quota-expire = "chatmaild.expire:quota_expire_main"
 chatmail-fsreport = "chatmaild.fsreport:main"
+chatmail-deferred = "chatmaild.deferred:main"
 lastlogin = "chatmaild.lastlogin:main"
 turnserver = "chatmaild.turnserver:main"
 

chatmaild/src/chatmaild/config.py

@@ -40,6 +40,9 @@ class Config:
         self.filtermail_http_port_incoming = int(
             params.get("filtermail_http_port_incoming", "10082")
         )
+        self.filtermail_lmtp_port_transport = int(
+            params.get("filtermail_lmtp_port_transport", "10083")
+        )
         self.postfix_reinject_port = int(params.get("postfix_reinject_port", "10025"))
         self.postfix_reinject_port_incoming = int(
             params.get("postfix_reinject_port_incoming", "10026")

chatmaild/src/chatmaild/deferred.py

@@ -0,0 +1,37 @@
+"""
+Analyze deferred mails and print most common failing destinations.
+
+Example:
+
+    python -m chatmaild.deferred
+"""
+
+import json
+import subprocess
+from collections import Counter, defaultdict
+
+
+def main():
+    p = subprocess.Popen(["postqueue", "-j"], text=True, stdout=subprocess.PIPE)
+    domain_reasons = defaultdict(Counter)
+    domain_total = Counter()
+
+    for line in p.stdout:
+        item = json.loads(line)
+        if item["queue_name"] != "deferred":
+            continue
+
+        for recipient in item["recipients"]:
+            _, domain = recipient["address"].rsplit("@", 1)
+            reason = recipient["delay_reason"]
+            domain_total[domain] += 1
+            domain_reasons[domain][reason] += 1
+
+    for domain, total in reversed(domain_total.most_common()):
+        print(f"{domain} ({total} recipients)")
+        for reason, count in domain_reasons[domain].most_common():
+            print(f"  {count}: {reason}")
+
+
+if __name__ == "__main__":
+    main()

cmdeploy/src/cmdeploy/filtermail/deployer.py

@@ -1,3 +1,5 @@
+import os
+
 from pyinfra import facts, host
 from pyinfra.operations import files, systemd
 
@@ -5,7 +7,7 @@ from cmdeploy.basedeploy import Deployer, get_resource
 
 
 class FiltermailDeployer(Deployer):
-    services = ["filtermail", "filtermail-incoming"]
+    services = ["filtermail", "filtermail-incoming", "filtermail-transport"]
     bin_path = "/usr/local/bin/filtermail"
     config_path = "/usr/local/lib/chatmaild/chatmail.ini"
 
@@ -13,11 +15,21 @@ 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}"
+        url = f"https://github.com/chatmail/filtermail/releases/download/v0.6.4/filtermail-{arch}"
         sha256sum = {
-            "x86_64": "48b3fb80c092d00b9b0a0ef77a8673496da3b9aed5ec1851e1df936d5589d62f",
+            "x86_64": "5295115952c72e4c4ec3c85546e094b4155a4c702c82bd71fcdcb744dc73adf6",
-            "aarch64": "c65bd5f45df187d3d65d6965a285583a3be0f44a6916ff12909ff9a8d702c22e",
+            "aarch64": "6892244f17b8f26ccb465766e96028e7222b3c8adefca9fc6bfe9ff332ca8dff",
         }[arch]
         self.need_restart |= files.download(
             name="Download filtermail",

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

@@ -0,0 +1,11 @@
+[Unit]
+Description=Chatmail transport service
+
+[Service]
+ExecStart={{ bin_path }} {{ config_path }} transport
+Restart=always
+RestartSec=30
+User=vmail
+
+[Install]
+WantedBy=multi-user.target

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

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

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

@@ -73,7 +73,7 @@ http {
 
 		access_log syslog:server=unix:/dev/log,facility=local7;
 
-		location /mxdeliv/ {
+		location /mxdeliv {
 		    proxy_pass http://127.0.0.1:{{ config.filtermail_http_port_incoming }};
 		}
 

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

@@ -79,22 +79,6 @@ inet_protocols = ipv4
 inet_protocols = all
 {% endif %}
 
-# Postfix does not try IPv4 and IPv6 connections
-# concurrently as of version 3.7.11.
-#
-# When relay has both A (IPv4) and AAAA (IPv6) records,
-# but broken IPv6 connectivity,
-# every second message is delayed by the connection timeout
-# <https://www.postfix.org/postconf.5.html#smtp_connect_timeout>
-# which defaults to 30 seconds. Reducing timeouts is not a solution
-# as this will result in a failure to connect to slow servers.
-#
-# As a workaround we always prefer IPv4 when it is available.
-# 
-# The setting is documented at
-# <https://www.postfix.org/postconf.5.html#smtp_address_preference>
-smtp_address_preference=ipv4
-
 virtual_transport = lmtp:unix:private/dovecot-lmtp
 virtual_mailbox_domains = {{ config.mail_domain }}
 lmtp_header_checks = regexp:/etc/postfix/lmtp_header_cleanup
@@ -109,3 +93,10 @@ smtpd_sender_login_maps = regexp:/etc/postfix/login_map
 # Do not lookup SMTP client hostnames to reduce delays
 # and avoid unnecessary DNS requests.
 smtpd_peername_lookup = no
+
+# Use filtermail-transport to relay messages.
+# We can't force postfix to split messages per destination,
+# when specifying a custom next-hop,
+# 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 }}

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

@@ -100,3 +100,8 @@ filter    unix -        n       n       -       -       lmtp
 # cannot send unprotected Subject.
 authclean unix  n       -       -       -       0       cleanup
   -o header_checks=regexp:/etc/postfix/submission_header_cleanup
+
+lmtp-filtermail unix  -       -       y       -       -       lmtp
+  -o syslog_name=postfix/lmtp-filtermail
+  -o lmtp_header_checks=
+  -o lmtp_tls_security_level=none

cmdeploy/src/cmdeploy/tests/test_helpers.py

@@ -1,11 +1,10 @@
-import importlib.resources
+from pathlib import Path
 
 from cmdeploy.www import build_webpages
 
 
 def test_build_webpages(tmp_path, make_config):
-    pkgroot = importlib.resources.files("cmdeploy")
+    src_dir = (Path(__file__).resolve() / "../../../../../www/src").resolve()
-    src_dir = pkgroot.joinpath("../../../www/src").resolve()
     assert src_dir.exists(), src_dir
     config = make_config("chat.example.org")
     build_dir = tmp_path.joinpath("build")

cmdeploy/src/cmdeploy/www.py

@@ -1,5 +1,4 @@
 import hashlib
-import importlib.resources
 import re
 import time
 import traceback
@@ -37,7 +36,7 @@ def prepare_template(source):
 
 
 def get_paths(config) -> (Path, Path, Path):
-    reporoot = importlib.resources.files(__package__).joinpath("../../../").resolve()
+    reporoot = (Path(__file__).resolve() / "../../../../").resolve()
     www_path = Path(config.www_folder)
     # if www_folder was not set, use default directory
     if config.www_folder == "":
@@ -133,8 +132,7 @@ def find_merge_conflict(src_dir) -> Path:
 
 
 def main():
-    path = importlib.resources.files(__package__)
+    reporoot = (Path(__file__).resolve() / "../../../../").resolve()
-    reporoot = path.joinpath("../../../").resolve()
     inipath = reporoot.joinpath("chatmail.ini")
     config = read_config(inipath)
     config.webdev = True

doc/source/overview.rst

@@ -153,6 +153,7 @@ Chatmail relay dependency diagram
         autoconfig.xml --- dovecot;
         postfix --- |10080|filtermail-outgoing;
         postfix --- |10081|filtermail-incoming;
+        postfix --- |10083|filtermail-transport;
         filtermail-outgoing --- |10025 reinject|postfix;
         filtermail-incoming --- |10026 reinject|postfix;
         dovecot --- |doveauth.socket|doveauth;
@@ -295,9 +296,7 @@ ensured by ``filtermail`` proxy.
 TLS requirements
 ~~~~~~~~~~~~~~~~
 
-Postfix is configured to require valid TLS by setting
+Filtermail (used for delivery) requires a valid TLS.
-`smtp_tls_security_level <https://www.postfix.org/postconf.5.html#smtp_tls_security_level>`_
-to ``verify``.
 
 You can test it by resolving ``MX`` records of your relay domain and
 then connecting to MX relays (e.g ``mx.example.org``) with