What are RBL, MAPS, reverse DNS, DCC, etc.?
The Realtime Blackhole List (RBL) is a blacklist on the Internet, made available under the umbrella of the Mail Abuse Prevention Systems (MAPS). It lists unprotected mail servers that are used by spammers for sending unsolicited mail. Mail servers using the RBL can deny communications with the listed systems. Because spammers are making increasing use of open client systems with changing IP addresses, the effectiveness of RBL has seen a sharp decline recently. Reverse DNS is part of the Internet`s Domain Name System. It is based on a reverse lookup process that checks the consistency of the name and IP address of the calling mail server by querying a DNS for the IP address and domain name. If any irregularities are detected, a connection is denied. There is a debate about the effectiveness of this method against spam since spammers often either use other peoples systems for sending spam or operate their own mail distribution systems. The Distributed Checksum Clearinghouse (DCC) is a ne
