It's easy to block all spam, if you don't mind also blocking legitimate mail. What's harder is being confident you're not blocking any legitimate mail. I'm gl

It's easy to block all spam, if you don't mind also blocking legitimate mail. What's harder is being confident you're not blocking any legitimate mail. I'm glad you've managed it :). I have Bayesian filtering behind DMARC checks and a few other DNS and RBL checks. Still not perfect -- for all folk talk of the difficulties getting mail accepted by the big providers, a surprising number of companies still don't have matching forward and reverse DNS records :P. One principle I follow is that I don't drop anything. Every message will either be rejected or delivered, with a narrow band of SpamAssassin scores that delivers to a spam folder.