I was actually recently discussing self-hosting email on Matrix a while ago, so I’ll just copy-paste below. Long story short, find the right existing email software you want to use, set it up correctly with a healthy IP address and domain (not blacklisted), the right DNS entries, and a PTR record, and it’ll work just fine.

Honestly, I haven’t had any issues with self-hosting email, and I’ve been doing it for the past 2 years. I think the trick is that you just need to set everything up correctly and then verify your setup with mail-tester.com to ensure all the headers, DNS entries, etc. are correct. There are some great projects that make it extremely easy to self-host, including Mailu github.com/mailu/mailu, Mailcow github.com/mailcow/mailcow-dockerized, Docker mailserver (https://github.com/docker-mailserver/docker-mailserver), Stalwart github.com/stalwartlabs/stalwart, and I’m sure more. I’m currently using Mailu, but I have been eyeing Stalwart, which has recently gotten quite popular and implements modern email protocols and does everything in Rust.

If I were you and just wanted to take a stab at self-hosting email, I would start with Stalwart and see how you like it. The only caveat is that it doesn’t yet come with a webmail client, so if you wanted one, you’d have to separately add that to your setup.

Something you would need to think about though is your IP address. It must be static, and it should be in a healthy IP address range (not on any popular blacklists). You also need to be able to set up rDNS (reverse DNS) / PTR record, so you can point your IP address back to your email domain.