[perlgod]

I used to run Postfix + Dovecot + Rspamd with all the bells and whistles enabled [1], but I recently switched to OpenSMTPD + spamd on OpenBSD.

Unlike rspamd, which has pluggable modules for everything under the sun (RBLs, word filters, Bayesian filtering + learning), spamd uses plain ol' graylisting with some PF integration to throttle spammers connections to 1 character/second for maximum annoyance.

With Rspamd, I never got any spam in my Inbox. With spamd, I get maybe 1 spam mail every two weeks. To me, spamd's ridiculous simplicity is worth the tradeoff.

You do have to be careful with graylisting large mailers like Gmail, since they rarely retry the mail from the same IP address. For this, OpenBSD's smtpctl now has the spfwalk [2] command to whitelist the big guys. That's what I use in my current setup [3], which was linked here a few days ago.

[1] https://www.c0ffee.net/blog/mail-server-guide/

[2] https://poolp.org/posts/2018-01-08/spfwalk/

[3] https://github.com/cullum/dank-selfhosted

[cristoperb]

For greylisting nowadays I use Postfix's builtin postscreen[1] along with a few DNS-based whitelists and postscreen_dnsbl_whitelist_threshold=-1 to make sure gmail etc don't get delayed. No extra software required. Though it would be nice if it had builtin ability to find IP addresses to whitelist via SPF.

I recently set up a small postfix+dovecot system, and postscreen with DNS blacklists alone seems quite effective. But I do plan to add spamassassin or rspamd or spamd at some point.

1: http://www.postfix.org/POSTSCREEN_README.html