docs: webdev needs to be exposed via nginx if run on the relay

remove mentions of the build machine / deployment server separation

.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
@@ -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/v0.6.6/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@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
+

chatmaild/pyproject.toml

@@ -10,6 +10,7 @@ dependencies = [
   "filelock",
   "requests",
   "crypt-r >= 3.13.1 ; python_version >= '3.11'",
+  "domain-validator",
 ]
 
 [tool.setuptools]

chatmaild/src/chatmaild/config.py

@@ -1,6 +1,8 @@
+import ipaddress
 from pathlib import Path
 
 import iniconfig
+from domain_validator import DomainValidator
 
 from chatmaild.user import User
 
@@ -8,30 +10,40 @@ 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"]
+        raw_domain = params["mail_domain"]
+        self.mail_domain_bare = raw_domain
+        self.ssh_host = params.get("ssh_host", 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:
+            DomainValidator().validate_domain_re(raw_domain)
+            self.ipv4_relay = None
+            self.mail_domain = raw_domain
+            self.postfix_myhostname = raw_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.max_mailbox_size = params.get("max_mailbox_size", "500M")
+        self.max_message_size = int(params.get("max_message_size", 31457280))
+        self.delete_mails_after = params.get("delete_mails_after", "20")
+        self.delete_large_after = params.get("delete_large_after", "7")
+        self.delete_inactive_users_after = int(
+            params.get("delete_inactive_users_after", 90)
+        )
+        self.username_min_length = int(params.get("username_min_length", 9))
+        self.username_max_length = int(params.get("username_max_length", 9))
+        self.password_min_length = int(params.get("password_min_length", 9))
+        self.passthrough_senders = params.get("passthrough_senders", "").split()
+        self.passthrough_recipients = params.get("passthrough_recipients", "").split()
         self.www_folder = params.get("www_folder", "")
         self.filtermail_smtp_port = int(params.get("filtermail_smtp_port", "10080"))
         self.filtermail_smtp_port_incoming = int(
@@ -53,7 +65,7 @@ class Config:
         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.iroh_relay = "https://" + raw_domain
             self.enable_iroh_relay = True
         else:
             self.iroh_relay = params["iroh_relay"].strip()
@@ -79,17 +91,17 @@ 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.get("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)
@@ -150,28 +162,13 @@ 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/ini/chatmail.ini.f

@@ -3,6 +3,9 @@
 # mail domain (MUST be set to fully qualified chat mail domain)
 mail_domain = {mail_domain}
 
+# Where to deploy the relay - if unspecified, mail_domain will be used.
+ssh_host = localhost
+
 #
 # If you only do private test deploys, you don't need to modify any settings below
 #
@@ -12,42 +15,42 @@ 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 =
+#passthrough_senders =
 
 # 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 =
+#passthrough_recipients =
 
 # Use externally managed TLS certificates instead of built-in acmetool.
 # Paths refer to files on the deployment server (not the build machine).
@@ -63,19 +66,11 @@ 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 +103,13 @@ 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

@@ -88,29 +88,27 @@ class MetadataDictProxy(DictProxy):
 
     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()
+                            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"
 
         logging.warning(f"lookup ignored: {parts!r}")
         return "N\n"
@@ -120,12 +118,13 @@ 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
 

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/tests/plugin.py

@@ -31,6 +31,11 @@ def example_config(make_config):
     return make_config("chat.example.org")
 
 
+@pytest.fixture
+def ipv4_config(make_config):
+    return make_config("1.3.3.7")
+
+
 @pytest.fixture
 def maildomain(example_config):
     return example_config.mail_domain

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):
@@ -9,10 +13,21 @@ 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_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, maildomain):
@@ -21,26 +36,17 @@ def test_read_config_basic_using_defaults(tmp_path, maildomain):
     example_config = read_config(inipath)
     assert example_config.max_user_send_per_minute == 60
     assert example_config.filtermail_smtp_port_incoming == 10081
-
-
-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 == []
+    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.passthrough_recipients == []
+    assert example_config.passthrough_senders == []
 
 
 def test_config_userstate_paths(make_config, tmp_path):
@@ -135,3 +141,17 @@ 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_metadata.py

@@ -360,15 +360,8 @@ 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"
@@ -383,3 +376,23 @@ 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_newmail.py

@@ -19,24 +19,35 @@ 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_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, maildomain, tmpdir, example_config):
     monkeypatch.setattr(chatmaild.newemail, "CONFIG_PATH", str(example_config._inipath))
     print_new_account()

cmdeploy/src/cmdeploy/cmdeploy.py

@@ -87,10 +87,12 @@ def run_cmd_options(parser):
 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.ssh_host
     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):
@@ -105,7 +107,7 @@ def run_cmd(args, out):
     pyinf = "pyinfra --dry" if args.dry_run else "pyinfra"
 
     cmd = f"{pyinf} --ssh-user root {ssh_host} {deploy_path} -y"
-    if ssh_host == "localhost":
+    if ssh_host in ["localhost", "@local"]:
         cmd = f"{pyinf} @local {deploy_path} -y"
 
     if version.parse(pyinfra.__version__) < version.parse("3"):
@@ -119,6 +121,8 @@ 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.")
         return 0
@@ -140,7 +144,11 @@ def dns_cmd_options(parser):
 
 def dns_cmd(args, out):
     """Check DNS entries and optionally generate dns zone file."""
-    ssh_host = args.ssh_host if args.ssh_host else args.config.mail_domain
+    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.ssh_host
     sshexec = get_sshexec(ssh_host, verbose=args.verbose)
     tls_cert_mode = args.config.tls_cert_mode
     strict_tls = tls_cert_mode == "acme"
@@ -177,7 +185,7 @@ 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.ssh_host
     sshexec = get_sshexec(ssh_host, verbose=args.verbose)
 
     out.green(f"chatmail domain: {args.config.mail_domain}")

cmdeploy/src/cmdeploy/deployers.py

@@ -370,7 +370,7 @@ 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)
@@ -469,7 +469,7 @@ 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)])
@@ -526,7 +526,7 @@ 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 +534,13 @@ 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/deployer.py

@@ -68,7 +68,7 @@ class DovecotDeployer(Deployer):
         )
 
     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):

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

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

@@ -20,10 +20,10 @@ 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}"
+        url = f"https://github.com/chatmail/filtermail/releases/download/v0.6.6/filtermail-{arch}"
         sha256sum = {
-            "x86_64": "5295115952c72e4c4ec3c85546e094b4155a4c702c82bd71fcdcb744dc73adf6",
-            "aarch64": "6892244f17b8f26ccb465766e96028e7222b3c8adefca9fc6bfe9ff332ca8dff",
+            "x86_64": "05c7e7ac244606c2eeb275f2d282ffdbc2403e0169f1cdd3110ffcebdb994a92",
+            "aarch64": "8cf8bbda4d907beca547b365cc7e6753532a74b1712492d0d2f3d2d8a553fb3d",
         }[arch]
         self.download_executable(url, self.bin_path, sha256sum)
 

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

@@ -54,14 +54,17 @@ smtpd_tls_exclude_ciphers = aNULL, RC4, MD5, DES
 tls_preempt_cipherlist = yes
 
 smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
-myhostname = {{ config.mail_domain }}
+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 %}
@@ -79,8 +82,6 @@ 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
 
 mua_client_restrictions = permit_sasl_authenticated, reject
@@ -102,3 +103,11 @@ smtpd_peername_lookup = no
 default_transport = lmtp-filtermail:inet:[127.0.0.1]:{{ config.filtermail_lmtp_port_transport }}
 lmtp-filtermail_initial_destination_concurrency=10000
 lmtp-filtermail_destination_concurrency_limit=10000
+
+{% 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

@@ -80,8 +80,9 @@ filter    unix -        n       n       -       -       lmtp
 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
+{% 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

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_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

@@ -15,7 +15,7 @@ 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
@@ -178,7 +178,7 @@ 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
@@ -10,19 +9,20 @@ import time
 from pathlib import Path
 
 import pytest
-from chatmaild.config import read_config
+from chatmaild.config import is_valid_ipv4, read_config
+from domain_validator import DomainValidator
+
+
+def format_mail_domain(raw_domain: str) -> str:
+    if is_valid_ipv4(raw_domain):
+        return f"[{raw_domain}]"
+    DomainValidator().validate_domain_re(raw_domain)
+    return raw_domain
+
 
 conftestdir = Path(__file__).parent
 
 
-def _is_ip(domain):
-    try:
-        ipaddress.ip_address(domain)
-        return True
-    except ValueError:
-        return False
-
-
 def pytest_configure(config):
     config._benchresults = {}
     config.addinivalue_line(
@@ -58,12 +58,12 @@ 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")
-def sshdomain(maildomain):
-    return os.environ.get("CHATMAIL_SSH", maildomain)
+def sshdomain(chatmail_config):
+    return os.environ.get("CHATMAIL_SSH", chatmail_config.ssh_host)
 
 
 @pytest.fixture
@@ -278,7 +278,6 @@ 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 +291,7 @@ 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 +316,8 @@ 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 +326,7 @@ 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
 
@@ -341,8 +341,9 @@ 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 = (
@@ -416,10 +417,10 @@ 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 +467,11 @@ 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 +482,7 @@ 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/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

@@ -23,8 +23,7 @@ def make_host(*fact_pairs):
         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}"
+                f"unexpected get_fact({cls.__name__}); only registered: {registered}"
             )
         return facts[cls]
 

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 +48,28 @@ 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/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

@@ -15,19 +15,15 @@ Minimal requirements and prerequisites
 You will need the following:
 
 -  Control over a domain through a DNS provider of your choice.
+   (there is experimental support for :ref:`IP-only relays <iponly>`).
 
--  A Debian 12 **deployment server** with reachable SMTP/SUBMISSIONS/IMAPS/HTTPS ports.
+-  A Debian 12 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
    chatmail addresses.
 
--  A Linux or Unix **build machine** with key-based SSH access to the root
-   user of the deployment server.
-   You must add a passphrase-protected private key to your local ssh-agent because you
-   can’t type in your passphrase during deployment.
-   (An ed25519 private key is required due to an `upstream bug in
-   paramiko <https://github.com/paramiko/paramiko/issues/2191>`_)
 
+.. _setup:
 
 Setup with ``scripts/cmdeploy``
 -------------------------------------
@@ -35,7 +31,7 @@ Setup with ``scripts/cmdeploy``
 We use ``chat.example.org`` as the chatmail domain in the following
 steps. Please substitute it with your own domain.
 
-1. Setup the initial DNS records for your deployment server.
+1. Setup the initial DNS records for your relay.
    The following is an example in the
    familiar BIND zone file format with a TTL of 1 hour (3600 seconds).
    Please substitute your domain and IP addresses.
@@ -55,22 +51,25 @@ steps. Please substitute it with your own domain.
       The ``mta-sts`` CNAME and ``_mta-sts`` TXT records
       are not needed for such domains.
 
-2. On your local PC, clone the repository and bootstrap the Python
+2. Login to the server with SSH, clone the repository and bootstrap the Python
    virtualenv.
 
    ::
 
+       ssh root@chat.example.org
        git clone https://github.com/chatmail/relay
        cd relay
        scripts/initenv.sh
 
-3. On your local build machine (PC), create a chatmail configuration file
+3. Then, create a chatmail configuration file
    ``chatmail.ini``:
 
    ::
 
        scripts/cmdeploy init chat.example.org  # <-- use your domain
 
+   .. note::
+
    To use self-signed TLS certificates
    instead of Let's Encrypt,
    use a domain name starting with ``_``
@@ -81,13 +80,7 @@ steps. Please substitute it with your own domain.
    See the :doc:`overview`
    for details on certificate provisioning.
 
-4. Verify that SSH root login to the deployment server server works:
-
-   ::
-
-       ssh root@chat.example.org  # <-- use your domain
-
-5. From your local build machine, setup and configure the remote deployment server:
+4. Now run the deployment script to install the relay to the server:
 
    ::
 
@@ -98,27 +91,41 @@ steps. Please substitute it with your own domain.
    configure at your DNS provider (it can take some time until they are
    public).
 
-Other helpful commands
-----------------------
 
-To check the status of your deployment server running the chatmail service:
+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.
 
-   scripts/cmdeploy status
 
-To display and check all recommended DNS records:
+Next Steps
+----------
+
+Now you should display and check all recommended DNS records
+to enable federation with other relays:
 
 ::
 
    scripts/cmdeploy dns
 
-To test whether your chatmail service is working correctly:
+You should also test whether your chatmail service is working correctly:
 
 ::
 
    scripts/cmdeploy test
 
+Other Helpful Commands
+----------------------
+
+To check the status of your chatmail relay:
+
+::
+
+   scripts/cmdeploy status
+
+
 To measure the performance of your chatmail service:
 
 ::
@@ -159,8 +166,9 @@ This starts a local live development cycle for chatmail web pages:
    directory and generating HTML files and copying assets to the
    ``www/build`` directory.
 
--  Starts a browser window automatically where you can “refresh” as
-   needed.
+-  if you are running scripts/cmdeploy webdev on the relay itself,
+   you need to configure a route in /etc/nginx/nginx.conf
+   to expose the build directory.
 
 Custom web pages
 ----------------
@@ -178,7 +186,7 @@ Disable automatic address creation
 --------------------------------------------------------
 
 If you need to stop address creation, e.g. because some script is wildly
-creating addresses, login with ssh to the deployment machine and run:
+creating addresses, login with ssh to the relay and run:
 
 ::
 
@@ -234,25 +242,3 @@ The deploy will verify that both files exist on the server.
    If you use such a setup, you must trigger the reload explicitly after renewal::
 
       systemctl start tls-cert-reload.service
-
-
-Migrating to a new build machine
-----------------------------------
-
-To move or add a build machine,
-clone the relay repository on the new build machine, and copy the ``chatmail.ini`` file from the old build machine.
-Make sure ``rsync`` is installed, then initialize the environment:
-
-::
-
-   ./scripts/initenv.sh
-
-Run safety checks before a new deployment:
-
-::
-
-   ./scripts/cmdeploy dns
-   ./scripts/cmdeploy status
-
-If you keep multiple build machines (ie laptop and desktop), keep ``chatmail.ini`` in sync between
-them.

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

@@ -265,7 +265,8 @@ 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