Reverse DNS Dig returning PTR results only with trace option

Raj Adhikari raj at
Tue Nov 10 21:48:42 UTC 2009

Thanks Chris for the reply.
Actually, let me put my question the other way.
How can one delegate the classless subnet to other DNS?
Actually, one of our ISP could not delegate classless subnet to our
server I am trying to help them in delegating the
classless subnet to us. So this scenario is simulating our ISP and us. I
was just testing with one of our other subnets checking if delegation
will work. Unfortunately, we both are using windows DNS. Windows just
have RFC 2317 way on configuring the delegation on it KB article using
CNAME, which I think has lots of problems. But I am following this BIND
way for delegation. I think, in windows the DNS configuration is more or
less similar to BIND.

In this scenario, lets say is my ISP and is us. owns and take a subnet 134.224/28 from them. So isn't
there a way for to delegate the subnet to Do again have to talk to their
upper ISP to delegate directly to us? What if upper ISP also need to ask
their upper tier ISP. It seems I am lacking some basic concept here
about the owner of the subnet. If a true owner delegates the subnet to
its client ISP, can't this ISP again delegate the classless subnet agin
to its client ISP?

Thank you,
Rajendra Adhikari

Chris Hills wrote:
> On 10/11/09 18:25, Raj Adhikari wrote:
>> Now I can do a dig for an hour or so. But again I run into same problem.
>> It wont return PTR record unless I explicitly do dig on
>> Also, the last did showing as Authority NS for this IP.
>> But trace showing as final sender.
>> Could someone shed a light on this?
>    86400   IN      NS      NS3.MCLEODUSA.NET.
>    86400   IN      NS      NS1.MCLEODUSA.NET.
>    86400   IN      NS      NS2.MCLEODUSA.NET.
> ;; Received 112 bytes from in 173 ms
> 7200 IN    NS
> 7200 IN    NS
> ;; Received 90 bytes from in 159 ms
> 3600 IN    NS
> 3600 IN    NS
> ;; Received 160 bytes from in 167 ms
> You should not chain a delegation in this manner. Either make the
> servers and authoritative for
> or have your ISP change the NS records to
> point directly to and
> The cyzap servers do not respond with the
> authority bit set ("aa" in dig).
> Regards,
> Chris
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