The Spam and Open Relay Blocking System


The SORBS (Spam and Open Relay Blocking System) 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. SORBS maintains 17 distinct DNSBL zones.

Listing Policy contains hosts that has been sent spam to actual SORBS administrators within the last 48 hours. Listing can also be triggered by spamtraps and honeypots. Continued spam coming from the same network will broadened the range of IP’s that is listed until the entire network has been blocked.