Basic clarifying questions about multi domains.

Hello all,

So as this year goal I have decided to reduce spending and one big chunk of yearly $ bleed is various hostings…

I can migrate the web stuff just fine and already did for most of my domains, to single server hosted in Hetzner ( these are non critical and if they go for a day or two before I restore nothing happens )… I use Traefik V3 as reverse proxy and bunch of docker containers with web stuff behind it.

I’m thinking migrating all the mail related stuff to this server as well, and Mailcow come highly recommended but I’m not clear on some things before I run it.

When creating the docker compose file I’m asked for mail.domain.com so I create DNS entry for one of my domains to point to to the server under mail.something.com

What is this domain used for ? How are handled other domains like I need mostly separate mails like:

mail@domain1.com
user1@domain1.com
mail@domain2.com
user1@domain2.com
etc…

from what I understand the mailcow have its web interface is this what the main mail.something.com is for ?or is it also for something else ?

Well thinking about it now, I might need to label the nginx container for each mail.<domain>.com I want to use ?

I’m confused about this a lot….