Tech Guides :: Email :: Realtime Black List
RBL Realtime Black List
The RBL is a list of IP addresses whose owners refuse to stop the proliferation of spam. Most mail server software can be configured to reject or flag messages which have been sent from a site listed on one or more such lists. The RBL usually lists server IP addresses from ISPs whose customers are responsible for the spam and from ISPs whose servers are hijacked for spam relay.
RBL was created in 1997 by Paul Vixie as part of his Mail Abuse Prevention System (MAPS). RBL falls under the general category of DNS-based Black lists (DNSBLs) of which several exist. In recent years, a number of DNSBLs have come under denial-of-service attacks, probably by spammers pressuring the DNSBLs to shut down.
As subscribers to the RBL, ISPs and companies will know from which IP addresses to block traffic. Most traffic blocking occurs during the SMTP connection phase. The receiving end will check the RBL for the connecting IP address. If the IP address matches one on the list, then the connection gets dropped before accepting any traffic from the spammer. Some ISPs, though, will choose to blackhole (or ignore) IP packets at their routers. The goal here is to block all IP traffic.
It is important to note that all e-mail and packet blocking is done by the recipient, not the RBL administrator, which is only responsible for bouncing spam that is directed at its servers.
The RBL was created by Mail Abuse Prevention System (MAPS) LLC., but there are other entities that keep RBLs aside from MAPS.
