Merge pull request #727 from usrpro/feat-subnet2

Move the Mailu Docker network to a fixed subnet.

docs/compose/.env

@@ -1,6 +1,5 @@
 # Mailu main configuration file
-#
-# Most configuration variables can be modified through the Web interface,
+## Most configuration variables can be modified through the Web interface,
 # these few settings must however be configured before starting the mail
 # server and require a restart upon change.
 
@@ -21,6 +20,9 @@ SECRET_KEY=ChangeMeChangeMe
 BIND_ADDRESS4=127.0.0.1
 BIND_ADDRESS6=::1
 
+# Subnet of the docker network. This should not conflict with any networks to which your system is connected. (Internal and external!)
+SUBNET=192.168.203.0/24
+
 # Main mail domain
 DOMAIN=mailu.io
 
@@ -64,9 +66,9 @@ ANTIVIRUS=none
 # Max attachment size will be 33% smaller
 MESSAGE_SIZE_LIMIT=50000000
 
-# Networks granted relay permissions, make sure that you include your Docker
-# internal network (default to 172.17.0.0/16)
-RELAYNETS=172.16.0.0/12
+# Networks granted relay permissions
+# Use this with care, all hosts in this networks will be able to send mail without authentication!
+RELAYNETS=
 
 # Will relay all outgoing mails if configured
 RELAYHOST=

docs/compose/docker-compose.yml

@@ -104,3 +104,11 @@ services:
     image: mailu/fetchmail:$VERSION
     restart: always
     env_file: .env
+
+  networks:
+    default:
+      driver: bridge
+      ipam:
+      driver: default
+      config:
+        - subnet: $SUBNET

docs/configuration.rst

@@ -24,6 +24,11 @@ The ``HOSTNAMES`` are all public hostnames for the mail server. Mailu supports
 a mail server with multiple hostnames. The first declared hostname is the main
 hostname and will be exposed over SMTP, IMAP, etc.
 
+The ``SUBNET`` defines the address range of the docker network used by Mailu.
+This should not conflict with any networks to which your system is connected.
+(Internal and external!). Normally this does not need to be changed,
+unless there is a conflict with existing networks.
+
 The ``POSTMASTER`` is the local part of the postmaster email address. It is
 recommended to setup a generic value and later configure a mail alias for that
 address.
@@ -40,9 +45,9 @@ be too low to avoid dropping legitimate emails and should not be too high to
 avoid filling the disks with large junk emails.
 
 The ``RELAYNETS`` are network addresses for which mail is relayed for free with
-no authentication required. This should be used with great care. It is
-recommended to include your Docker internal network addresses if other Docker
-containers use Mailu as their mail relay.
+no authentication required. This should be used with great care. If you want other
+Docker services' outbound mail to be relayed, you can set this to ``172.16.0.0/12``
+to include **all** Docker networks. The default is to leave this empty.
 
 The ``RELAYHOST`` is an optional address of a mail server relaying all outgoing
 mail.