The SORBS (Spam and Open Relay Blocking System), owned and operated by Proofpoint, Inc., provides free access to its DNS-based Block List (DNSBL) to effectively block email from more than 12 million host servers known to disseminate spam, phishing attacks and other forms of malicious email. The list typically includes email servers suspected of sending or relaying spam, servers that have been hacked and hijacked, and those with Trojan infestations. In an attempt to provide preemptive protection, SORBS also lists servers with dynamically allocated IP addresses.
Approximately 200,000 organizations worldwide leverage the SORBS including government organizations such as the Australian Communications and Media Authority, the Australian Federal Police and U.S.'s Federal Trade Commission.
If anyone would like to contribute to SORBS or has any suggestions for new detection routines, and/or hosts to be listed, the SORBS team would love to hear from you. Please use the Mail/Contact Form to get in touch and discuss your thoughts.