DNS server in Windows 2003 AD not able to resolve internet requests

[MTK1008]

I am trying to make some changes to my company's network. We have AD setup, the server is setup as the DC and also as a DNS server on the network. This DNS server is used for Domain users on the network. We also have another DNS server that was setup before the company started to use AD, and that is what most users point to. We are trying to get rid of that machine and make the DNS server on the DC the primary.
The problem I have is when I turn off the old DNS server, I can no longer access the internet, everything local works fine. The old DNS server is setup as the a forwarded in the DC DNS server. Root Hints are setup, but it does not seem to be getting to the root hints. I can not find a "." zone, but under my cache directory there is a local host entry that points to the ip 127.0.0.1. I clear the cache, but it stays. My theory is that this loopback is making the DNS server the last choice for DNS resolution unless there is a forwarded setup. The only thing I can do to the entry is delete it, and I can not add a new entry under the Cache. I am a little hesitant in deleting a file I can not recreate or back up. Does anyone know if this file is important or I can delete it?

 

[jimdwa]

It probably won't matter if you delete it. Your default hosts file has an entry for localhost to 127.0.0.1. Hosts is read before dns so you'll get resolved anyway. But this isn't your problem. Currently you say that the AD DNS server forwards to the old DNS server? If this is true then can you forward to another recursive DNS server such as one at your ISP?

Jim
Network Engineer
MCSE,Net+,CCNA,Sec+

 

[MTK1008]

Yes I can forward to my ISP also, but although that would be a work around I was hoping not to do that.
In looking at it some more, it seems that it is able to resolve some internet address, but not any main/poplar ones things like .edu can get resolved. My plan at this point is that I setup a DNS server on another DC and copied over all the zones. The new DNS server works fine, so I will change all my servers that have static entries to include this new DNS server, and setup DHCP to push it all to all workstions. At that point I will blow away DNS on the main server and reinstall.
I hate to go through all this work, but we can not seem to see what is causing the problem with the orginal DNS server, and since the person who orginally setup it up is gone, this might be my best solution at this point.