====== Some notes regarding Mailcow Dockerized ======

Some time ago, I started investigating several self-hosted mail solutions.

I recently settled on using https://mailcow.email/

Because I am doing this on a couple of Proxmox machines at home, port 25 is blocked by my ISP, so I swiched to using a smarthost for relay

This showed a couple of interesting things

== 1. The mailcow unbound server does not follow /etc/resolv.conf, it needs to be manually configured if you are also hosting internal zones ==

Solution: Edit the file data/conf/unbound/unbound.conf and add entries per self-hosted zone:

<file conf data/conf/unbound/unbound.conf>
  forward-zone:
    name: "internal.home.arpa"
    forward-addr: 10.10.53.1
  </file>

Obviously, change the values to match your settings

== 2. Because I am using a smarthost, emails coming from inside the LAN would go out to the smarthost and then get back in again, wasteful ==

Solution: Edit the file data/conf/postfix/custom_transport.pcre and add entries per self-hosted domain:

<file conf data/conf/postfix/custom_transport.pcre>
/domain-2.arpa$/ :
/domain-2.arpa$/ :
/domain-3.arpa$/ :
</file>

This is a regex filter, so the slash and the dollar-sign+slash at the end are needed

You can also add a value, something like this:

'' /domain-4.arpa$/ : [smtp] smart-host-something.com''

But that can be done from the Mailcow admin GUI.

Good luck