Dear/madam,
I am documenting this migration for reference purpose only. Our mail infrastructure at OVHcloud was running SpamAssassin since 2019 itself. Kindly note the following observations:
1) SpamAssassin configuration is 3400+ lines. Rspamd equivalent is 900 lines only.
2) SA uses Perl regex. Rspamd uses Lua. The translation itself took forty hours.
3) Our false positive rate changed from 0.3% to 0.7%. This is unacceptable only.
The nightmare itself: SA's `score USER_IN_BLACKLIST` became Rspamd's `multimap { type = "from"; map = "/etc/rspamd/blacklist.map"; score = 6; }`. Simple, yes, but we had 47 such rules.
Then the twist, kindly prepare yourself. Forty percent of our "spam" folder was actually our own newsletter bounces. The client had misconfigured SPF itself. Rspamd was correct. SA had been hiding this.
I am requesting your guidance: is this migration worth completing, or shall we revert?
