Rbldnsd

Gotchas, when setting up a domain, unless the zone is 100% dedicated to the task of serving RBL's, you have to set up your DNS server to forward queries to it. Like so for sbl.atomicorp.com:

zone "sbl.atomicorp.com" {
         type forward;
         forward only;
         forwarders {
               82.165.186.20;
       };
 };