I recently setup a new Windows 2003 domain with about fifteen Windows XP SP1 workstations. These PCs were migrated from a Windows 2000 domain. I took the Windows 2003 Domain Controller Policy from another one of our networks with exactly the same setup, just a different domain name. The network policies seem to work fine until several hours later when the users cannot access the DC (also our file server). I double-checked the policy and block inheritance is checked, and the policy does not seem to change. If I re-import the old policy and run gpupdate to refresh it, and the users login/logout it works fine again until a few hours later when access is blocked to the server.
I am not running any firewall software and the Windows XP firewall is disabled. All PCs can see each other and connect at all times, even when they cannot connect to the DC.
Does anyone have any suggestions to resolve the problem, or determine the source of the problem?
Thanks for your help!