In addition to checking the IPs of the connecting servers against the SBL, you can significantly boost your spam catch rate by also scanning the email body of any mails that get past SBL/XBL looking for host names of URLs (web sites) advertised in spams, and checking the IPs of those hosts, and their names servers, against the SBL. This is because the SBL lists the IPs of spammers' websites in addition to their mail servers. This feature ("URIBL_SBL") is available in SpamAssassin 3.0, and code to do this is also available as a sendmail milter from here.

The above statement is referring to SpamHaus project. I would like to be able to set this up so it looks through e-mail body etc as outlined above and configure the system accordingly.