Our PDC server (W2K Sp4) is running AD, however when I try and open AD users & computers I get the message "Naming information cannot be located because: The server is not operational. Contact you system admin to verify that your domain is properly configured and is currently online." We have been getting this for some time now. Recently I installed w2k sp4 as we were running sp3, I have also checked the ip filtering is set to "permit all". any solutions ?