Unable to log on to Exchange Server from a Windows 2000 or Windows XP client

When you try to use Outlook to log on to an Exchange Server computer, you may receive one of the following error messages: There is no loss of connectivity from the computer that is running Windows 2000 or Windows XP. Remote procedure call (RPC) connectivity works, you can open a shared list on the Exchange Server computer, you can log on to the Microsoft Windows NT Server 4.0 domain, and you can ping by name and by Internet Protocol (IP).

To resolve this problem, remove and re-add Transmission Control Protocol/Internet Protocol (TCP/IP) in the Local Area Connection properties:

1. Double-click the My Computer icon, double-click Control Panel, and then double-click Network and Dial-Up Connections.
2. Click Local Area Connection, click Properties on the File menu, and then click to clear the Internet Protocol (TCP/IP) check box.
3. Install another protocol (NWlink or NetBEUI) to maintain a placeholder for each connection.
4. Restart your computer, double-click the My Computer icon, double-click Control Panel, and then double-click Network and Dial-Up Connections.
5. Click Local Area Connection, click Properties on the File menu, and then click to select the Internet Protocol (TCP/IP) check box to add TCP/IP.

For more information about this process, click the following article number to view the article in the Microsoft Knowledge Base: The article contains the following procedure to remove TCP/IP from your Windows 2000-based computer:

1. Click to clear the TCP/IP check box from all dial-up connections and all LAN connections in the Network and Dial-up Connections tool.
2. Install another protocol (NWlink or NetBEUI) to maintain a placeholder for each connection.
3. Restart your computer.
4. Reinstall TCP/IP, and then restart your computer.

If the computer is a domain controller, the procedure is different. For more information about how to remove and reinstall TCP/IP on a Windows 2000 domain controller, click the following article number to view the article in the Microsoft Knowledge Base:

For more information, click the following article number to view the article in the Microsoft Knowledge Base: