>On Fri, 28 Jan 2000 itojun@iijlab.net wrote:
>> "127.0.0.rev" supplies 0.0.127.in-addr.arpa. (contains "1")
>> "0000:0000:0000:0000.rev" supplies 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.int.
>> 	(contains "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0")
>> "0.0.0.rev" supplies 0.0.0.in-addr.arpa. (contains "1")
>Sounds good - but what is 0.0.0.1 (in v4)? 

	IPv6 spec defines the following:
	- if first 96bit is 0, it is v4 compatible address.  this appears in
	  RFC1993 in "automatic tunnelling" section.  by sending packet to
	  ::10.1.1.1, it will appear on wire as "IPv6 packet tunnelled in
	  IPv4, and the IPv4 destination is 10.1.1.1".
	- however, if 127bits are 0 and the last one is 1, it is loopback
	  address.  (::1 is loopback address).

	Some of IPv6 old resolver code (not ours) mistakingly queries
	1.0.0.0.in-addr.arpa against ::1, which is bit-pattern identical
	with ::0.0.0.1.  So having 1.0.0.0.in-addr.arpa. record helps those
	old and broken resolver code.

	Since this is an workaround, I'm okay to omit 0.0.0.rev.

itojun