Surblhost is a small program to see if hostnames are listed in the Spam
URI Realtime Blocklists (SURBL).

Hosts that are blacklisted means that global spam email have been reported
to contain links to these hosts.

Many popular spam email filters use these lists to identify spam email,
but this program makes it possible to use the lists for any conceivable
purpose, such as filtering out bad hosts from URL redirection, and so on.