I have a new Exchange 2007 Server that has been running ok for a couple months. On Friday morning I decided to go ahead and restart the servers that had updates. After the restarts Exchange can no longer communicate with the GC. I have three domain controllers. 2 are Windows 2000 and the 3rd is 2003 R2. The 2K3 server holds the GC and is the Schema master. Exchange is totally ignoring this 2003 server that is the only one it will work with and is trying to get GC info from the 2K servers.Exchange is still processing mail and all but a few users mail boxes are working. I cannot log into the console nor do any management of the server however. I have no idea how to get it to communicate with GC. I am new to '07 as the last Microsoft email server I took care of was 5.5! Does anyone know where to start? I suspect it is DNS.?.?I am a couple days away from demoting both 2K servers and installing a second 2K3 DC should I just leave it alone and deploy the new server?

I agree with your Dns holds the records of the servers that are GC. If the 2K3 is a Dns too can locate de records and the primary dns must be this server for the exchange. My sugestion is not to migrate from so far versions. Complete the demotion of 2K and trasnfer all the master roles to the 2K3 with integrated Dns.