This is kind of newbie question... I googled about this scenario,
but with no results :(

Lets say I have fictivedomain.com registered with ns1.fictivedomain.com
(10.20.30.1) and ns2.fictivedomain.com (10.20.30.2) that serve as
Primary DNS servers on machine #1.

Recently I acquired machine #2 on completely different subnet and now I
want to setup ns3.fictivedomain.com (40.50.60.1) and
ns4.fictivedomain.com (40.50.60.2) on this machine #2, and I want them
to serve as Primary DNS servers as well (I plan to shut down machine #1
eventually).

So far, I have:

- installed MS DNS onto Win2003 SE
- created ns3 and ns4 host names (Record Type A) with associated IP
addresses (40.50.60.1 and 40.50.60.2) in fictivedomain.com host records;
- Windows TCP/IP properties -> DNS server addresses are set to
40.50.60.1 and 40.50.60.2;
- MS DNS set to listen to all IP addresses (got 4 of them on machine)
- created Primary Forward and Reverse Lookup Zones

Forward Lookup Zone screenshot:
http://img151.imageshack.us/my.php?image=msdnsconfig1ni7.gif

Reverse Lookup Zone screenshot:
http://img166.imageshack.us/my.php?image=msdnsconfig2vh6.gif

- tested DNS with DNSTester and the results were okay (server responded)

The problem? When I try to modify DNS settings in client's .com domain,
and enter ns3.fictivedomain.com and ns4.fictivedomain.com, it returns
error every time and values are not saved. If I try to enter ns1 or ns2,
then it goes trough...

Hope I didn't complicate it... Any help appreciated. Thanks!

m.