[dxld]

I've been really impressed with Mox, an all-in-one monolithinc mail system written in go: https://www.xmox.nl

Trivial to setup, guides you through configuring SPF, DKIM, DMARC, MTA-STS, DANE and DNSSEC. Handles certificates by itself through ACME, comes out-of-the-box with IP/domain reputation based and bayesian spam filtering.

While I've come to appreciate how much tweaking you can do with something like exim I'm starting to see the advantage of not having to spend time doing any of that :)

Mox also has some really cool (and AFAICT) novel features stemming from the fact that it's so tightly integrated. Have a look at the "Rejects" mailbox, or the nuanced way it rejects spam at SMTP time to prevent the dilemma between causing backscatter or potentially dropping mails (like gmail likes to do). I've also never heard of REQUIRETLS before seeing it exposed right there in Mox's built-in webmail.

[is_true]

Have you tried mailinabox (https://github.com/mail-in-a-box/mailinabox)?

If so, what do you think.