[Pdns-users] Retry NXDOMAIN with a secondary forwarder

[Erik Weber]

On Mon, Jan 9, 2012 at 11:30 AM, Richard Connon <conan at irconan.co.uk> wrote:
> On 08/01/2012 21:55, Erik Weber wrote:
>>
>> On Sat, Jan 7, 2012 at 6:30 PM, Richard Connon<conan at irconan.co.uk>
>>  wrote:
>>>
>>> On 07/01/2012 17:24, Peter van Dijk wrote:
>>>>
>>>> On Jan 7, 2012, at 4:45 , Richard Connon wrote:
>>>>
>>>>> Is it possible through lua scripting or otherwise to configure powerdns
>>>>> to look NXDOMAIN responses up in a second forwarder before returning
>>>>> NXDOMAIN.
>>>>> To clarify I'd like it to go something like:
>>>>>
>>>>> lookup name in NS1
>>>>> if found in NS1:
>>>>>    return NS1 result
>>>>> else:
>>>>>    lookup name in NS2
>>>>>    return NS2 result
>>>>
>>>> Taking one step back: what actual problem are you trying to solve here?
>>>
>>> I want to overlay a set of names onto an existing DNS zone for which I
>>> don't
>>> control the nameserver.
>>> I have a number of names which are "mine" inside a zone managed "higher
>>> up"
>>> my organisation. The zone also contains lots of names which are not
>>> "mine".
>>> DNS updates can take over 3 weeks (ridiculous, no?) to happen on the
>>> actual
>>> organisational nameservers so I want to make a resolver which will
>>> reflect
>>> our changes immediately.
>>
>> Could you possibly access "your" data by any other means than DNS
>> (like database or something)? If so, couldn't you just write a plugin
>> that checks your backend for the record and otherwise just return to
>> normal lookup mode?
>
>
> I could do that. How difficult would that be? At the moment I wouldn't know
> where to start.

Take a look at the sample here: http://doc.powerdns.com/recursor-scripting.html

You'd have to write some lookup code (to the database) and correctly
build the return packet.
The first thing I'd do is make some code that does the lookup when run
directly, then try to fit that into a PowerDNS-script.

Some more info at http://wiki.powerdns.com/trac/wiki/Lua

-- 
Erik