XGEN: The "DisableNetLogonCheck" Registry Value and How to Use It

This article provides information about the DisableNetlogonCheck registry value and how to use it.

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.


The version of DSAccess that is included with Exchange 2000 Server Service Pack 2 (SP2) and later makes a call to the NetLogon service of each domain controller and global catalog server that DSAccess discovers. This is a remote procedure call (RPC) from the Exchange 2000 server to the domain controller. Therefore, the call fails if RPC connectivity is blocked.

DSAccess recognizes that the port is probably blocked and still considers the domain controller "up." However, each call takes an unusually long time to fail. Each call also degrades DSAccess startup and failover performance.

You can use the DisableNetlogonCheck registry value to turn off this check against all of the domain controllers and save the time that it takes to make the failed calls. The DisableNetlogonCheck registry value is very useful on any server that does not have RPC connectivity to all of the domain controllers in the same site as the Exchange 2000 server. To use the DisableNetlogonCheck registry value, you have to edit the registry.

To disable the calls to the NetLogon service for each domain controller and global catalog server that Exchange 2000 discovers, add the DisableNetlogonCheck value:

1. Start Registry Editor (Regedt32.exe).
2. Locate and click the following key in the registry:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeDSAccess
3. On the Edit menu, click Add Value, and then add the following registry value:
   Value name: DisableNetlogonCheck
   Data type: REG_DWORD
   Value data: 1
4. Quit Registry Editor.

For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base: More information is also available in the Microsoft Exchange 2000 Server Service Pack 2 Release Notes. You can find that information at the following Microsoft Web site: