I have one user's workstation that from time to time has trouble connecting via Remote Desktop to some (not all) of our Windows Server by name. I tested connectivity using ping. From his workstation, I could ping these servers by IP address. I could not ping the servers by their DNS server name. Out of the 5 servers I tested, the workstation only had trouble pinging 2 of them by name, so it is not like DNS was completely dysfunctional. He is pointing to our Active Directory Domain Controller as his primary DNS and then has a secondary DNS to our Internet providers DNS server in case our DC ever goes down. This same config is in place on all of our workstations as far as I know. Both times that this has happened (several weeks apart), I can run an ipconfig /flushdns and everything is back to normal. The workstation is Windows 7 Pro 64-bit. Any ideas?