>> >> >> >> >> >> I'm trying out a new idea for blacklisting hosts. I have >> >> several email >> >> servers for processing spam. These servers service my lowered >> >> numbered >> >> >> > >> > As others said, not a good idea. >> > >> > Don't bother BL isting them, if they hit your dummy mx record, they die, >> > don't retry, and have in effect blacklisted themselves. >> > >> > >> >> What I see happening is that they are hitting MX randomly. So some times >> they hit a good server and sometimes they hit the trap. Once they have >> hit the trap several times then they are blacklisted in my hostkarma >> blacklist and if they hit a real server they are rejected at connect time. >> >> On my servers less than 1% of all email attempts make it as far as spam >> assassin. This reduces it further. >> >> A simpler approach might be to blacklist senders that try multiple non-existent recipients, regardless of mx priority
BTW: at one time I was quite happy with some pre-filtering on my private mail (which is fetchmail ultimately feeding to SA) until I found that SA would no longer recognize some spam in the bayes section. So, if capacity permits, it might be a good idea to feed (a random sampling of) pre-filtered spam to sa-learn Wolfgang
