How to filter spam with Rspamd

Rspamd analyzes every message and gives it a spam score based on several signals: sender reputation, content, authentication. It is faster than the old SpamAssassin.

If you use Mailcow

Rspamd comes already included and configured. You manage it from the web interface, where you see statistics and can adjust thresholds.

Manual install

apt-get update -y
apt-get install -y rspamd
systemctl enable --now rspamd

How the score works

• Below a threshold: the message passes.
• Above a threshold: it is marked as spam or moved to the spam folder.
• Above a higher threshold: it is rejected outright.

Important signals

Rspamd checks the sender's SPF, DKIM and DMARC, so your correct configuration helps on the receiving side too, see SPF, DKIM and DMARC.

Fine tuning

Periodically review messages wrongly marked as spam (false positives) and adjust the rules. A too aggressive filter hides legitimate email, a too permissive one lets spam through.