You've learned about filtering spam using spamd and by strengthening Postfix, Linux.com's Murthy Raju adds more tools to your Postfix-based spam busting techniques. Coupled with SpamAssassin, Realtime Blackhole Lists (RBL) and Distributed Checksum Clearinghouse (DCC) provide a way to determine if the source of the spam e-mail has already been identified as spam by other systems.

If you know of other ways to help combat spam e-mail, then we'd greatly appreciate it if you will share it here. Now, I hope that there is a way to use these tools on blog comment spammers. :P