I am trying to track down the best of the open source email offerings and figure out which is good, which is bad, what is unique and why to choose one over another. So far, these are the known high end candidates of which I am aware.
Does anyone have any input into what is good or bad, or any candidates that are missing from the list? I've not included some things like RoundCube which is just a client and not an email system. RoundCube could be used with any of these products, for example.
I'm a big fan of the classic Postfix + Dovecot (still in use/maintained?) + MariaDB/MySQL/PostgreSQL + SpamAssassin + ClamAV + Sieve + Roundcube combo. There's a pretty cool managesieve plugin for Roundcube which allows you to create filters from within the webmailer.
But it's a lot of work to get everything running.
Sounds like https://mailinabox.email/