Help with the subzone problem

[Tech W.]

Hello,

I found a strange problem.

We have a zone in Bind, for example, abc.com
We designate a subzone of it to another dns server, for eaxmple, F5's 3DNS.

The corresponding RR in Bind is:

games.abc.com.  IN  NS  3600  ns1.example.com.
games.abc.com.  IN  NS  3600  ns2.example.com.

Bind's setup is OK.
Both ns1 and ns2.example.com are the domain names for 3DNS.

But F5's 3DNS can't setup the NS records for games.abc.com.
That means, when query to:

dig games.abc.com ns @ns1.example.com

get nothing.

So, under this case though most time the people's query is OK, but the windows DNS Server we noticed, doesn't behave well sometime.

If windows DNS (Cache Server) doesn't have games.abc.com 's NS records cached, any query to games.abc.com will get an empty response. For example, query to www.games.abc.com will get nothing if the peer is windows DNS server and at that time the server doesn't have games.abc.com's NS records in its cache.

So is this my problem or F5's problem or windows DNS server problem?

Thanks!

Kind regards,
Ken.