I have 4 2003 servers with sp1 installed and 1 existig NT4 BDC which has exchange 5.5 stil installed on it. All mail has been migrated to the 2003 server.. 1 is a 2003 domain controller, 2 are file servers and the 4 is a 2003 exchange server. The exchange server isnt resolving dns properly.. All other workstations and servers are fine. I can ping by ip address, server name but not the FQDN on the 2003 Exchange server. All other machines can ping and recieve replies all 3 ways... As you can guess being an exchange server this is causing all kinds of problems. Getting errors in the system event log (5790) No suitable doman controller is available for domain (mydomain). An NT4 or older domain controller is availabel but cannot be used.... It all seems to be caused by DNS not working properly... any suggestions?