The naive approach of reversing the address, converting to nibbles and appending a suffix won't scale. For IPv6 if you did the reverse of /48, /52, /56, /60 and /64 prefixes, which matches delegation patterns along with NXDOMAIN synthesis, you would still be fine. You stop the search on NXDOMAIN or data with perhaps a new value which says to continue searching for white listed records. One could even start with /32 if one is worried about spammers pretending to be ISPs.
I don't necessarily disagree, but now you've just upgraded the DNS (NXDOMAIN synthesis is far from universal) and layered a probing protocol on top of it. We can have a theological argument about whether that counts as "using the DNS".
R's, John _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf