rbls {
   nixspam {
       symbol = "RBL_NIXSPAM";
       rbl = "ix.dnsbl.manitu.net";
       ipv4 = true;
       ipv6 = true;
   }
   gbudb {
       symbol = "RBL_GBUDB";
       rbl = "truncate.gbudb.net";
       ipv4 = true;
       ipv6 = true;
   }
}