On 28.04.2010, at 09:31, Mark Scholten wrote:
Hmm. A macro expansion for a /48 would mean 1,208,925,819,614,629,174,706,176 leaves. An interesting stress test for name servers... :-).
With LUA scripting and PowerDNS you could create a reverse DNS/ forward DNS based on the input and match it (IP or hostname). This could be really dynamic and with using some cache it should also be fast. Checking what IPv6 address is in use and providing them a rDNS is also an option of course (but I think that will consume more power/bandwith/etc. on the long term).
Lua scripting is available for PowerDNS recursor only i fear, you would want a authoritative DNS solution here and there already is one: This script [1] by Wijnand Modderman is a pipe backend for PowerDNS Server which will provide you with IPv6 forward and reverse entries much like DJB's walldns does for IPv4. Due to the way backends are exhausted for answers subsequently in PowerDNS Server i can have my mysql backend provide IN AAAA and PTR records for hosts that i want named specifically and then let the pipe backend handle all the rest of my /48.
Slightly more seriously, there have been discussions in the past about doing dynamic synthesis of v6 reverses, but that gets icky (particularly if you invoke the dreaded "DNSSEC" curse) and I don't know any production server that actually does this now. Dynamic DNS is probably the least offensive solution if you really want reverses for your v6 nodes.
As long as you don't use DNSSEC the option above is possible, but with DNSSEC many options will fail I think. Completely dynamic based on the request of a client isn't an option if you ask me (or do we want .local addresses in the rDNS?).
DNSSEC support for PowerDNS Server is on it's way [2] and i think it should integrate with most available backend types not for long, however whats still missing is indeed the dynamic DNS support aka TSIG - i don't need it but i happen to know there have been a few requests for DDNS support in PowerDNS recently, so maybe that will happen too. Stefan [1] http://zaphods.net/~zaphodb/pdns-ipv6-reverse-backend.py [2] http://mailman.powerdns.com/pipermail/pdns-users/2010-April/006671.html