I am unsure if this problem has been addressed before. I have a DNS
reverse-lookup problem.

I have two domains, Domain A and Domain B. Domain A is a W2K
native-mode domain. Domain B is a Win NT4.0 domain. Domain A uses
AD-integrated DNS. Domain B uses a UNIX DNS server. Domain A's W2K DNS
server forwards unresolved DNS queries to Domain B's UNIX server.
Computer Comp1, IP 10.6.49.132, is in Domain A. Computer Comp2, IP
10.0.33.51, is in Domain B.

From within Domain A, the commands NSLOOKUP COMP1 and NSLOOKUP
10.6.49.132 both produce the correct results, i.e., Comp1's IP address
and Comp1's FQDN, respectively. From within Domain B, the commands
NSLOOKUP COMP2 and NSLOOKUP 10.0.33.51 both produce the correct
results, i.e., Comp2's IP address and Comp2's FQDN, respectively. In
other words, DNS lookup and DNS reverse-lookup within each domain
works OK. Also, from within Domain A, NSLOOKUP COMP2 produces the
correct result, 10.0.33.51.

Here is my problem: From within Domain A, NSLOOKUP 10.0.33.51 gives an
error message: "(Domain A's DNS server FQDN) can't find 10.0.33.51:
Non-existent domain".

In the DNS table of Domain A, under Reverse Lookup Zones, there is an
entry 10.in-addr.arpa.

What is wrong, and how can I fix this reverse lookup problem?

Thank you.

Nick