The Mail Abuse Protection System’s Realtime Blackhole List (MAPS RBL) is a dynamically updated list of known unsolicited bulk email (UBE) sources identified by source IP address. The Messaging Server SMTP server supports use of the RBL and can reject mail coming from sources identified by the RBL as originators of UBE or spam.
Implementing an RBL should be a consideration of every deployment. In general, a good RBL deployed in front of MTAs reduces traffic to the MTAs by a minimum of 10 percent, and in some cases, much higher.
RBLs, and anti-spam and anti-virus servers, such as BrightMail, can work together. For example, if your anti-spam server rejects 95 to 99 out of 100 emails from a particular IP address, you can add that IP address to the RBL. You can also adjust the RBL for BrightMail’s false positives when you conduct your BrightMail analysis. Thus, you make the RBL much more proactive in handling a specific wave of UBE.
See Sun Java System Messaging Server 6.3 Administration Reference for information on configuring the ENABLE_RBL option of the MTA Dispatcher.