I found a similar post, but I don’t think it quite answered my question.
First, mailcow version: 2024-06c

I have two separate domains (more coming, moving off SmarterMail on expensive VPS). Let’s call the domains: a.com and b.com. I have all the right DNS entries for mail.a.com and mail.b.com, all the testing is working, all the sending and receiving is working (now that I disabled IPv6 so Gmail will let me in). I’ve since restarted all the docker containers, as well.

When I go to https://mail.a.com to get to the webmail UI, it’s fine. But when I got to https://mail.b.com I get browser alerts telling me that the SSL cert is for mail.a.com, not mail.b.com. To be clear, these are NOT domain aliases. These are separate domains with separate admins and mailboxes.

I don’t want to have to put Traefik in to manage this, that just seems like dumb overhead I don’t need. I must be missing something. I’m no nginx expert, not even close (never even worked with it). What I read about “creating separate sites” can’t be right. I must be missing something to get SANs into the LetsEncrypt certs?

Any insight would be much appreciated. Thanks!

  • If you want your SSL certificate to include additional SANs you have to define them in your mailcow.conf

    ADDITIONAL_SAN=mail.*

    and restart your stack

    docker compose down
docker compose up -d

    See https://docs.mailcow.email/post_installation/firststeps-ssl/#additional-domain-names

    Just out of curiosity, because in the last weeks/months a lot of already answered and well documented questions are posted here, were you aware of the official mailcow documentation? There even is a link to the docs at the top of this forum 😃

If you want your SSL certificate to include additional SANs you have to define them in your mailcow.conf

ADDITIONAL_SAN=mail.*

and restart your stack

docker compose down
docker compose up -d

See docs.mailcow.email Icon Advanced SSL - mailcow: dockerized documentation

docs.mailcow.email Icon docs.mailcow.email
Advanced SSL - mailcow: dockerized documentation
None
docs.mailcow.email

Just out of curiosity, because in the last weeks/months a lot of already answered and well documented questions are posted here, were you aware of the official mailcow documentation? There even is a link to the docs at the top of this forum 😃

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    DocFraggle Thank you for the information. I guess however I searched for my question (via Google), I must have phrased it incorrectly. Pretty sure my search should’ve been mailcow additional san (because I just now tested it and it took me straight to it).

    Just an oversight on my part, honestly, to not look for it the docs. Lots on my mind right now; poor excuse. Will be sure to check them better than I did for this for future questions first.

    Thanks for being helpful about it, when most would’ve just been jerks!

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