Subnet reverse delagation, RFC 2317

[Phil Mayers]

On 29/07/10 12:34, Jukka Pakkanen wrote:
> 29.7.2010 14:23, Mark Andrews kirjoitti:
>> In message<4C5134AF.2080302 at qnet.fi>, Jukka Pakkanen writes:
>>
>>> Doing first time the RFC 2317 style subnet reverse DNS, and have a
>>> problem with recursion.  When doing a query like "dig @ns1.qnet.fi -x
>>> 62.142.217.200" is succeeds from the local network, but outside I get
>>> "recursion requested but not available".  Our /24 reverse zones work
>>> fine, the server knows it's the master and serves ok, like "dig
>>> @ns1.qnet.fi -x 62.142.220.5".
>>>
>> There is NOTHING wrong here.  You are not testing the servers properly.
>>
>
> Uuh... NOW I'm confused :)
>
> There's definitely something wrong somewhere, because reverse-DNS for
> 62.142.217.128/25 is not working as it should.
>
> ns1.qnet.fi should be the authoritive reverse DNS server for that IP
> range, but it's not serving. Getting "recursion requested but not
> available".

No - Mark is right (apologies for my confusing posts). Assume an example 
IP of 62.142.217.200. Your server is authoritative for:

200.128/25.217.142.62.in-addr.arpa.

...not:

200.217.142.62.in-addr.arpa.

ns{3,5}.sci.fi have CNAMEs linking the two because they own the parent 
zone, so can answer a "dig -x THEIP" directly.

$ dig @ns3.sci.fi 200.217.142.62.in-addr.arpa ptr

;; QUESTION SECTION:
;200.217.142.62.in-addr.arpa.	IN	PTR

;; ANSWER SECTION:
200.217.142.62.in-addr.arpa. 14400 IN	CNAME 
200.128/25.217.142.62.in-addr.arpa.
200.128/25.217.142.62.in-addr.arpa. 86400 IN PTR x200.qnet.fi.