Question : Reverse NSLOOKUP request not being forwarded from DCs to outside DNS servers

I have a strange problem:
I have 2 AD sites with 2 DCs in each site. All DCs are DNS servers and I am using AD integrated DNS. Internal DNS has no issues. In one site, when I try to do a "nslookup " to get reverse-dns, I consistantly get a "DNS Request timed out. timeout was 2 seconds" the same lookup works fine on both DCs in the other site. I have the ISP's DNS setup as forwarders and NSLOOKUP attaching to the ISP DNS show the nslookup results correctly and very quickly. It appears that for reverse lookup, the two DCs for some reason are not forwarding the request. Any ideas?

Answer : Reverse NSLOOKUP request not being forwarded from DCs to outside DNS servers

You'd have to take a look at what the server is doing with the request. Either with Debug Logging (DNS Console / Server Properties) or with a packet sniffer.

A time-out implies a network connection issue, so I'd expect to find the query going out, but no reply coming back in.

Chris