The Mail Abuse Protection System’s Real-time Blackhole List (MAPS RBL) is a dynamically updated list of known UBE sources identified by source IP address. The Messaging Server SMTP server supports use of the MAPS RBL and can reject mail coming from sources identified by the MAPS RBL as originators of UBE. The MAPS RBL is a free service provided through the Internet DNS.
For more information, see:
Use of the RBL by the Messaging Server SMTP server is enabled with the ENABLE_RBL option of the MTA Dispatcher.