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

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/mtail.service.j2

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

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"
+
+