Cool. I'd split dnsbl_zones into ipv4_dnsbl_zones and ipv6_dnsbl_zones and have the DnsblZones directive work like;DnsblIPv4Zones DnsblIPv6Zones or similar. IPv6 RBL's do exist, and are incompatible with IPv4 ones, so it's worth having the support early-on.
I haven't found any examples of IPv6 RBLs. Could you point me to one? What I'm finding on the web and usenet is that there is still no established standard for IPv6 blocklists. Unless I can find some reference, any implementation I make would be a guess so I'm leaving this unsupported right now.
