Article ID: 978363 - View products that this article applies to.
You experience performance issues in Microsoft Office Communications Server 2007 R2 during NTLM authentication. These performance issues may trigger one or more of the following symptoms:
These issues occur when both of the following conditions are true:
To fix this problem, apply the following update:
(http://support.microsoft.com/kb/977345/ )Description of cumulative update for Office Communications Server 2007 R2: January, 2010
To work around these issues, make sure that the delay is acceptable on the network links between the Office Communications Server 2007 R2 front-end server and its domain controller.Also make sure that the delay is not too long on the network links between that domain controller and the domain controllers for the user authentication domain.
Note The network link delay in seconds should be less than the number of Netlogon secure channels (default is 2) divided by the expected number of user logons per second. For example, for a delay of 0.1 seconds, the logon rate should not exceed 20 per second.
If you cannot decrease the network link delay, try to increase the
MaxConcurrentApiregistry entry for Netlogon on the server and on the server's domain controller.
For more information about the MaxConcurrentApi registry entry, click the following article numbers to view the articles in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/326040/ )How to configure an ISA Server computer for a very large number of authentication requests
(http://support.microsoft.com/kb/246118/ )How to configure your IAS server for a very large number of authentication requests