My Exchange server has stopped responding to Outlook clients via TCP/IP. RPC still works, but that means users can’t check their mail when someone else is logged in (network security in the email client is set to ‘none’). The error message the users receive in this case is “Unable to open your default e-mail folders. You do not have permission to log on.”
The RPCPing utility on the Exchange CD confirms that named pipes is working but TCP/IP is not. I can ping the server and connect to file shares successfully, and TCP/IP is the only protocol loaded, so the problem appears to be Exchange specific.
I’ve reviewed various MS KB articles, starting with Q244523, Q170637, Q174701, Q163576, Q155831, and Q176466. I’ve tried changing the TCP/IP ports static (as if they were connecting through a firewall) with no change.
We recently installed Exchange Service Pack 3, NT SP6A, and turned off some unused services (Proxy Server, SQL server, and Site Server, NetBEUI, Network Monitor Agent).
This is a single, isolated Exchange server with only an Internet connector.