Wrote a fake POP3 server the other day, as part of a project
here at my ISP. The idea
is that if you haven't paid your
bill, the radius server notices this and gives you a special
IP address. Then our Layer-4 switch routes all your POP
traffic to my fake server, where there is only one message,
saying 'pay your bill!'. Similar with port 80 (http), and
the rest goes nowhere.
It works fine for me through telnet, netscape, fetchmail, etc., but Outlook Express and Outlook both hang after RETR 1. Driving me nuts.