feat: support setup without domain, with only an IPv4 address (#963)

* dovecot: enable login names with square brackets

* config: make IPv4-only relays use self-signed TLS certs

* postfix: make delivery for IP-only relays work

* cmdeploy: skip DNS checks for IPv4 only relays

* www: generate dclogin codes for IPv4-only relays

* opendkim: disable DKIM signing on ipv4-only relays

* get delivery working

* get tests working on IPv4 only machine

* doc: document IPv4-only relays

* dns: warn if mail_domain is an IP, instead of checking DNS

* config: validate domains when formatting them

* ci: add cmlxc testing for no-DNS relays

* ci: run no-dns and normal CI in parallel

* retain "config.mail_domain" as the domain part of @ email addresses, so for ipv4 relays  "[1.2.3.4]" and introduce config.ipv4_relay and config.mail_domain_bare helpers.

* ci: migrate from --no-dns to --type ipv4 for cmlxc compatibility

* cleanup dead code, fix docs, fixate cmlxc version

---------

Co-authored-by: missytake <missytake@systemli.org>

.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@v0.14.6
+    with:
+      cmlxc_version: v0.14.6
+      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
@@ -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@v0.14.6
     with:
-      cmlxc_version: v0.13.5
+      cmlxc_version: v0.14.6
       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
+