We recently renumbered (for the first, and I hope the last time), and in the process, the question of IPv6 adressing came up; how do you assign static IPv6 addresses within a given /64?
I won't be going into the full discussion of the various different strategies, but I'll say that one element of the solution chosen was that if you had an IPv4 address ending in .123, you'd also get an IPv6 address ending in ::123. (IPv6-only hostnames would be handled differently.)
But then, how do you make sure the reverses are in sync? For some reason, BIND doesn't have a good way of synthesizing a PTR name from an IPv6 address, so you're stuck with typing 3.2.1.0.0.0.0.0.0.etcetcetc and hope you got everything right. It's a pain.
So instead, behold:
$ORIGIN 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.4.f.9.2.c.7.6.0.1.0.0.2.ip6.arpa. $GENERATE 1-9 $.0.0 CNAME $.52.35.193.in-addr.arpa. $GENERATE 0-9 $.1.0 CNAME 1$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.2.0 CNAME 2$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.3.0 CNAME 3$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.4.0 CNAME 4$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.5.0 CNAME 5$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.6.0 CNAME 6$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.7.0 CNAME 7$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.8.0 CNAME 8$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.9.0 CNAME 9$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.0.1 CNAME 10$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.1.1 CNAME 11$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.2.1 CNAME 12$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.3.1 CNAME 13$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.4.1 CNAME 14$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.5.1 CNAME 15$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.6.1 CNAME 16$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.7.1 CNAME 17$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.8.1 CNAME 18$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.9.1 CNAME 19$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.0.2 CNAME 20$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.1.2 CNAME 21$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.2.2 CNAME 22$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.3.2 CNAME 23$.52.35.193.in-addr.arpa. $GENERATE 0-9 $.4.2 CNAME 24$.52.35.193.in-addr.arpa. $GENERATE 0-4 $.5.2 CNAME 25$.52.35.193.in-addr.arpa.
and voila:
pannekake:~> host 2001:67c:29f4::50 0.5.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.4.f.9.2.c.7.6.0.1.0.0.2.ip6.arpa is an alias for 50.52.35.193.in-addr.arpa. 50.52.35.193.in-addr.arpa domain name pointer pannekake.samfundet.no.
Instant IPv4/IPv6 sync.