On Thursday, the team behind the SURBL domain blacklists announced a new, experimental blacklist: xs.surbl.org.

As announced on the SURBL-Announce list: “An experimental source of some snowshoe and pill domains is now being published in xs.surbl.org.  SURBL considers this feed to be experimental and would very much welcome feedback about it, particularly about any false positives.  Does anyone know anyone who actually wants to receive snowshoe messages?”

You can read the entire announcement here.

So what’s different about this blacklist/blocklist?

Most blacklists or blocklists are IP based, e.g they contain a list of computers and servers which have sent spam in the past. However because of the increased use of botnets (compromised computers) to send spam SURBL have for a while now maintained a list of websites advertised within spam messages. This allows mail administrators to add another useful tool to their content filtering e.g check for known websites known to be associated with spam.

SURBL claim that using these types of lists combined with traditional blocklists upto 95% of spam can be blocked.

This particular blocklist from SURBL focuses on pill and snowshoe websites.