Reverse DNS for IPv6 client networks

Stefan Schmidt zaphodb at zaphods.net
Tue Sep 14 09:51:54 CDT 2010


On Tue, Sep 14, 2010 at 02:38:35PM +0200, Jeroen Massar wrote:
> Instead of handpicking names or letting people insert data into your DNS
> servers, some people are deploying PowerDNS with custom backends for
> this that either convert the IPv6 address into a 128bit hex number,
> optionally stripping the first 64 bits and replacing that with 'autogen'
> or 'wlan-' or similar. Something else that I have seen is that the
> backend randomly picks a name from a dictionary and then assigns that
> 'statically' to that address.

As i repaired my adaption of Wichert Modderman's PowerDNS ipv6
forward/reverse walldns-style backend just yesterday, this is probably
the right moment to share it [1] with you.
It works with netaddr [2] > 0.7, however beware of an odd issue [3] with
PowerDNS and python's sys.platform.

The good thing about PowerDNS is that it is modular, so you can run several
backends and type of backends at once which will get exhaused for queries in
the order they are specified. [4]
With a pipebackend such as the aforementioned beeing called _after_ your
regular authoritative backend, you can have customized records for certain
ipv6 addresses in your ranges while still providing a consistent mapping of
forward and reverse records for the gazillion of ipv6 addresses.

$ dig @mandelbrot.zaphods.net -x 2001:67c:1400:1220::af +short
node-4v.ipv6.zaphods.net.
$ dig @mandelbrot.zaphods.net aaaa node-4v.ipv6.zaphods.net +short
2001:67c:1400:1220::af

	Stefan

[1] http://zaphods.net/~zaphodb/pdns-ipv6-reverse-backend.py
[2] http://code.google.com/p/netaddr/
[3] http://code.google.com/p/netaddr/issues/detail?id=59
[4] http://doc.powerdns.com/modules.html
[5] http://wiki.powerdns.com/trac

PS: find the powerdns community [5] on #powerdns @ irc.oftc.net
-- 
Hardware is the part of a computer system you can kick.
Software is what makes you want to kick the hardware.




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