I have been running some very busy mail (250k+ emails per day across several thousand users and mailing lists) servers for some time. I am using qmail with vpopmail and all that is fine without any problems.
One question I have which is not really server related but it still maybe interesting.
I am using rblsmtpd with about 6 black list servers currently that is eliminating around 90% of the spam alone. One thing I am interested to know from peoples experience. If a spammer never sees the email get through does that mean that they will eventually remove that email from the list or will they keep on sending email to that address until .....
any feedback would be good.
I don't really the think the spammer concentrates on whether it "gets through" unless the message bounces back because the address can't be reached. But even then, a lot of this stuff is automated, and the reply-to addresses are fake, or never checked, so even those bounce-backs are probably never received.