On Sat, Jan 04, 2003 at 10:22:58PM +0000, T wrote:
> I have a question on reverse look up. 

> When trying to test if everything is working  ok i used the dig command.

> If I use the command “dig ftp.mylan.cxm everything looks to work
> correctly. 

> If I use the command “dig 192.168.1.79”,
> it will not give me the host name ftp.mylan.cxm 

> anyway I am not sure if I have something messed up or not.
> any input would be appreciated.

There are a couple of issues here.  

The first is that forward lookups and reverse lookups are from
different zones and are delegated by different people.  If you have a
domain named example.com, your name servers are delegated that zone by
the TLD com.

reverse lookups are delegated from in-addr.arpa.  If 192.168.0.0/16
was not an unroutable address, it would be delegated from the netblock
owner for 192.168 as a delegation of the zone 168.192.in-addra.arpa.
In your above example, 192.168.1.79 would be a part of the zone
1.168.192.in-addra.arpa.  Since it is a part of the unroutable network
blocks, it has been delegated to the blackhole name servers at
iana.org.  This has been done because so many people have
misconfigured networks using these addresses without correctly
configuring their name server(s) to answer for the reverse zones.
See this:  http://www.as112.net/

Assuming that you were using the above address as an example, you
might want to check the FAQ on this topic:
	 http://dougbarton.net/bind-users/FAQ.html#RealNames

Your reverse zone will need to be delegated to you by the netblock
owner, which is a separate process from the registration of names in
the forward lookups.

In your named.conf files, you will have two zones defined, like this:

zone "example.com" IN {
     // example zone for documentation purposes only, per RFC 2606
        type master;
        file "example.com";
};

zone "1.168.192.in-addr.arpa" IN {
     // non-routable network.  all queries for this should be caught
     // by local name servers.
        type master;
        file "192.168.100.rev.zone";
};

HTH.

				 -rob

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