I need to run my own email server for some of my domains, because the providers that I usually use don’t support them (they use Unicode characters, and not everyone supports that yet). I have a small VPS that I run a few Docker containers on, and I’m wanting to try and run an email server on it as well. What containers are good for a low-hassle email setup? I don’t need a mailbox webui (ex: round cube), but it would be nice to have a UI for management. I do need multi-domain support, however.
Mailcow-dockerized. I’ve used it for nearly a decade, it’s been flawless. Very easy to set up with the admin webpage and has a webmail client, or use Roundcube with it.
Make sure you have your DKIM, SPF and Dmarc records in order and tested against MXtoolbox before you start.
What happens if your server is offline and an email comes in? I’m genuinely curious what it would do. Or must you VPS host your mail server for maximum uptime?
The other server sends again until it times out? Never been an issue, that’s just how email works. Most SMTP servers will attempt for a few days if they know the MX is valid. Besides, I’ve never been out for longer than an hour or two.
All MTAs have retries baked in, so running a self-hosted email server that receives mail is actually one of the most forgiving services in this respect. If your server is offline, the sending server will retry several times over 24-48 hours before it gives up. Even the big cloud email providers will do this.
That said, there are other aspects of running an email server that require some extra rigour, but they’re more on the sending side (making sure emails you send to other people actually land in their inbox). Doable, but one of the more challenging things to self-host.
What’s the resource usage like? I’ve looked into mailcow before but the recommended system specs are too expensive to make it worth it on a VPS.
Seems really low. I run it on a docker LXC with Nextcloud and bunch of other stuff, on 8 cores of an ancient dual Xeon Dell. I never seem to have to deal with latency on it.