[quyse]

If you are familiar with NixOS, and like to have everything declared in Nix configuration, Simple NixOS Mailserver is very robust and easy to use. Have been using it for ~2 years.

https://gitlab.com/simple-nixos-mailserver/nixos-mailserver

[chalst]

Checking the Gitlab summary, this is a wrapper around Postfix+Dovecot, with support for DKIM/SPF/DMarc authentication and rspamd spam filtering.