Named error on a firewall

[Takács István]

Hi,

We have a firewall, which has a corporate
unregistered IP address.
Our router do NAT for it, because our
public IP address set up on the router's
external interface, and forwards every
packets to the firewall.

That's why when I want to test our primary
name server, which runs on this firewall, 
start nslookup, it writes that the
192.168.1.1 has no registered name.

It's correct, because it serve name 
service for that IP which is on the router.

How can I set up this named to serv
the name service as a primary without
any error, but don't have to change it's 
IP to a registered one?

Thanks in advance!

Regards,

		Istvan