Re: How do you do rDNS for IPv6 ?

[Jared Mauch <jared () puck nether net>]

On Dec 5, 2010, at 9:41 PM, Jima wrote:

> On 12/5/2010 4:13 PM, John Levine wrote:
> > In IPv4 land, it is standard to assign matching forward and reverse
> > DNS for every live IP, and a fair number of services treat requests
> > from hosts without rDNS with added scepticism. For consumer networks,
> > it's often something like 12-34-56-78.adsl.incompetent.net, with the
> > numbers being the IP address forward or backwards.
> >
> > So if every customer gets a /64, what do you do?  You can use a
> > wildcard to give the same rDNS to all 2^64 addresses, but you can't do
> > matching forward DNS, since a DNS response with 2^64 AAAA records
> > would be, ah, a little unwieldy.
>
> I thought the same thing, actually, which is why I made my own solution.  I ended up writing a DNS server in perl 
> (using Net::DNS::Nameserver) that replies to reverse queries with a reproducible PTR -- generated by encoding the IP 
> in base32.  (Or the second half of the IP, in the case of a few "known" networks.)  Forward queries for the matching 
> name decode the base32.
> The host-specific part of the DNS is kind of long (26 characters, or 13 for known networks), but it's marginally 
> shorter than the full IP (which would be 32/16 characters, without separators).  I'm pretty happy with the results, 
> but I'd love to hear if anyone's come up with more elegant solutions.

Anyone done this dynamic synthesis w/ bind?  dnssec thoughts as well?  i know this isn't namedroppers, but perhaps 
someone can post some code or examples, or a link to a webpage with them? 

- Jared