Until this summer we have been running an NT4 domain on our campus. We added (did not migrate) a Win2k3 Domain this summer and are partially through moving accounts to the new domain. We have established trusts between the two domains (for access to each side during the move) and haven't had any problems up to today. This morning we began receiving errors that machines couldn't log on to the NT4 domain because it wasn't avaliable. We haven't changed anything on the network or servers since yesterday.
We can log on locally to the NT4 DCs, but when we try to log on from a client it won't authenticate. We've restarted servers, the NETLOGON service specifically, and also tried promoting one of our BDCs to see if there was an issue with our PDC. No matter what we try we can't log in to the NT4 domain any longer.
Anyone have any ideas to check? I've double checked WINS and the 1b and 1c entries are resolving correctly. Any other paths to troubleshoot?