IPv6 is tomorrow's internetwork
protocol -- perennially, it seems. BIND has supported IPv6 forward
and reverse-mapping since Version 4.9.5, released way back in 1996.
BIND 9, finally, added support for IPv6 as a transport, responding to
queries received over IPv6.
The IETF -- the body that develops
extensions to DNS, among other things -- briefly flirted with a
very complex method of handling IPv6 forward and reverse-mapping,
using A6 and DNAME records and "bitstring
labels." (Unfortunately, I wrote the fourth edition
of DNS and BIND at just the wrong time and
documented A6 and the rest.) Eventually, however, they opted to
standardize on a system that uses AAAA and PTR records in a
straightforward way, similar to the way A and PTR records work with