Spam and Open relay systems - http (SORBS-HTTP)
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.
Listing is automatic when you have a proxy identified by a SORBS testing machine or by one of the other known proxy lists or DNS based block lists.
We monitor this blacklist since 2015-01-01. More information: http://www.sorbs.net/