Outlook Clients Cannot Connect to an ISA Server-Published Exchange 2000 Server

If you try to connect from an Outlook 98 or an Outlook 2000 Service Pack 2 (SP2) client to an Exchange 2000 server that was published by using ISA Server Publishing, you may not successfully connect.

If you create a new profile, you may receive the following error message:Or, when you try to connect, you may receive the following error message:

This behavior occurs because the connection behavior in Outlook 98 and Outlook 2000 SP2 has changed to enable the load balancing of the global catalog servers. When the Outlook client starts, it asks the Exchange 2000 server for a global catalog server. This query may interrupt the Server Publishing of Exchange 2000 remote procedure call (RPC) servers because, for security reasons, the Microsoft Internet Security and Acceleration (ISA) RPC Filter only maps RPC endpoint connections. The RPC Filter in ISA gracefully terminates the connection when it receives this query.

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
To work around this behavior, you must hardcode the global catalog name for each client that you want to connect to the Server Published Exchange 2000 server. This hardcoded global catalog server is defined on a per user basis.

To hardcode the Outlook client to use the same name as the clients use to connect to Exchange 2000 when Server Published through ISA, use the following steps:

1. Click Start, click Run, type regedt32 to open the Registry Editor, and then click OK.
2. Locate, and then click the following key in the registry:
   HKEY_CURRENT_USER\Software\Microsoft\Exchange\Exchange Provider
   Note: You may have to create both the Exchange key and the Exchange Provider key.
3. On the Edit menu, click Add Value, and then add the following registry value:
   Value name:DS Server
   Data type: REG_SZ
   Value data: GC server name
4. Quit the Registry Editor.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

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