We have our 2003 domain up and running for years. I have run Forest and Domain prep. I now have (3) 2008 AD / DNS servers running. My last 2003 server is ready to be shutdown. It was an AD server. Ran DCpromo on it to remove the AD roles. Now it just sits there. No file shares. No DHCP. No AD. It seems to be the key to our whole building getting out to the internet. Every time I shut it down the users (about 100) can't get to the internet for the most part. Some can once in a while. Some pages (very few) load but slowly. most just can't get out at all.
I have physically been to each machine and all DNS setups point to the new 2008 servers. We don't run any type of proxy so it was not a proxy ever.
I just ran a packet capture and the 2003 server is doing DNS Query and Response to my 2008 boxes and a few users PC's.
Any ideas as to what I am missing?