Adam Hardy wrote:
[snip]
sorry if this is a dumb question, but your email implies spam-assassin does DNS look-ups to filter out spam - which is not what I thought after giving spam assassin the once-over check-out. Is it so? What level of effectiveness does it have?I am using DNS and DCC checking here with spamassassin. Also with the "rules du jour" additions which update blacklist files a couple of times a week. The results after three months or so are 100% spam-catching and no false positives, though I did start out with a well-trained bayes db. The nice aspect of this is that I can now blackhole spam mail with a score of more than, say, 15 without having to worry about losing genuine mails.And can it actually filter your pop3 server's inbox before download?
However, this is just on a home set-up with +/- 400 mails a day, mostly from mailing lists. Since each email has to be checked online, so to speak, things do slow down and if traffic on the net is heavy it can take up to around 5 seconds for SA to check each email. For only a few emails, this doesn't matter but if you had thousands it would be very hard, I imagine. Even so, this has provided the missing ingredient that's turned spam filtering from "so-so" to very good.
I don't know the answer to your second question as I run exim4 as my own mailserver, so everything gets downloaded before handing off to SA. Doesn't sound very likely, though.
:) Fish