John Kelly wrote:
Every day, I get mail delivery attempts to non-existent users like: k2159jcd003343@isp2dial.com k1mmcsoa007563@isp2dial.com k1nardpb001747@isp2dial.com These totally bogus user names are not a good dictionary attack. I don't know what the spammer is trying to accomplish, since delivery is impossible. The user portion almost looks like a mail queue message id. Anyone else seeing this?
I've found that greylisting (postgrey) helps tremendously with crap like that.
-Jim P.