how DNS client perform reverse lookup

[Keith Ng]

Barry Margolin wrote:
> In article <ct3ioj$1qll$1 at sf1.isc.org>, Keith Ng <ngkeith at triumf.ca> 
> wrote:
> 
> 
>>Hi,
>>
>>Would someone tell me how DNS client perform reverse lookup? Is there 
>>any root servers like forwards lookup for the in-addr.apra domain?
> 
> 
> They start from the normal root servers.  These servers have delegation 
> records for in-addr.arpa, just like they do for com, net, etc.  The 
> client servers follow this reverse delegation in exactly the same way 
> that they follow forward delegations.  As far as the nameservers are 
> concerned, there's no difference between forward and reverse DNS; 
> everything is just arbitrary labels to the servers and resolvers.
> 
Thanks guys,

I did not realize that the root servers for TLD are also responsible for 
the in-addr.arpa domain.

Now it is making sense to me.

Thanks again

Keith