Two slave on Master

[Julian]

Hi,
I have on master dns running on linux, and one slave running on winnt
and another slave running linux.

server names:

server1 Linux master
server2 Linux slave
server3 NT slave

Most of the updates are done on the linux master, while the NT slave
will update itself the linux slave won't.

The most worrying problem I have is when I try to register a domain to
host a site, the host checking program at domain registration page spits
out an error like this,

server1 does not list server2 as NS server server2.

I get the same error if I use server3 as slave.
How do I tell server1 that server 2 or 3 is a NS and to recognize it

Thanx
Julian  msmith at a2.com.au