About SMTarPit
I wrote this program because I looked around the Internet for an SMTP Tarpit/Honeypot that was: written in Perl; and, was only an SMTP tarpit/honeypot - I couldn't find one.
SMTarPit is a combined SMTP honeypot and tarpit released under the GPL. It is writen in Perl so it should work on virtually any platform that supports Perl (except Windows). It uses xinetd which looks at port 25 (instructions in the tarball) and when someone calls it, smtarpit is launched and then it chroots itself. It then decides whether there is a man or a machine on the other end and sets about wasting their time.
There are plenty of instructions as to how to configure the program - if Perl is not your first language, you should still be able to see what to do. You will certainly need to put a valid domain name in there but it is all well laid out so that you can install it and run it as a part of xinetd.
If you are an ISP with a tarpitted connection, you can tell which one it is from the fact that the tarpitted connection has a paritcular profile of inactivity and persistancy that no normal SMTP connection has. With this in mind, you can look at your RADIUS logs and take action on the spammer - the one thing that you know from monitoring the connection is that there will be many mails to the same domain from the same source address and that none of them will be solicited as there is in reality nobody to solicit them. Unsolicited bulk email equals spam and with the RADIUS logs, you can notify the authorities and have the spammer arrested and procecuted - or do nothing more than throw them off and let them spam another day. All spam connections are logged by the tarpit.