So, the nice antispam filtering system I had built for snafu has come tumbling down in ruin, as the load of spam that the system gets has been driving it to the point that it literally kills the machine it's on (load between 20.0 and 43.5). Users were unhappy, because the system was unusably slow.
So I tried bidding farewell to SpamAssassin, and checking out DSpam. DSpam was written in C rather than Perl, and supposedly designed to handle bayesian filtering for an entire site. Well, DSpam /definitely/ didn't kill things as badly. But even with what I could give it as a corpus, it caught maybe 0.5% of the spam on the system. Everyone's mailboxes were flooded, and even the training didn't seem to help much. Users were unhappy, because they couldn't get their real mail, and because training things seemed irritating to them.
I am now trying to build a separate machine which will handle the spam-filtering. Unfortunately, Postfix, for some ungodly unknown reason, does not want to pick up LMTP from anything but localhost. (Please note, I've created a test LMTP feed /specifically/ for this, which should pick up the LMTP from that one remote machine just fine.) Plus, I'm not confident that spamassassin will not kill /that/ machine as well, even though it's more powerful.
So, does anyone know of any antispam package which can handle a small ISP (about 30 users) which gets an inordinate amount of spam due to hosting several domains? I can't afford to spend $2000/yr on licensing one of the commercial packages, and I'm really at my wits' end about this. I need working antispam on Noderunner, but I need noderunner working also, so that I'm not completely buried. :(
Advice/input very, very, VERY appreciated.