Users experience delayed logins when you enable Password Management features in ISA Server 2006

When you enable the "Allow users to change their passwords" option on the Web listener used for publishing Exchange Server, your users experience delays while logging in to Outlook Web Access (OWA). The delay occurs after the user enters his credentials and clicks on the Log On button in the�OWA logon form. You are using ISA Server Forms-Based Authentication. ISA Server 2006 is�running on a�Windows Server 2003-based computer with Service Pack 2 or the Scalable Networking Pack installed.

This problem occurs because of a problem that exists in NAT in Windows Server 2003. This problem is exposed when you enable one of the following features on a network adapter that meets the NDIS 5.2 specification or a later version of this specification:
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• Receive Side Scaling (RSS)
• TCP/IP offloading

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Windows Server 2003 SP2 and the Windows Server 2003 Scalable Networking Pack include features to implement stateful and stateless offloading. The offloading feature accelerates the Windows networking stack. The networking update that is included in Windows Server 2003 SP2 and in the Windows Server 2003 Scalable Networking Pack includes the following features:
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• TCP Chimney Offload
• Receive Side Scaling
• Network Direct Memory Access (NetDMA)
  

A problem exists that affects NAT when you have Receive Side Scaling enabled. Therefore, after you install Windows Server 2003 SP2 or the Windows Server 2003 Scalable Networking Pack on a�computer running ISA Server, you experience the symptoms that are mentioned in the "Symptoms" section.

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system.�We cannot guarantee that these problems can be solved. Modify the registry at your own risk.
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To resolve this issue, certain registry changes need to be made on the ISA Server computer(s) publishing the Outlook Web Access service. If you are using ISA Server 2006 Enterprise Edition and you have enabled Network Load Balancing (NLB), you should perform these steps on each node in the array.
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1. On the Start menu, click Run.
2. Type regedit.exe and click OK.
3. Modify the following registry keys:
   
   ? Set the value of the registry key�HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\EnableRSS to 0 (zero).
   ? Set the value of the registry key�HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\EnableTCPA to 0 (zero).
   
4. From a computer on the external network, try to login to Outlook Web Access. If the delayed logins still persist, continue with steps 5 and 6.
5. Modify the following registry keys:
   
   ? Set the value of the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\EnableTCPChimney to 0 (zero).
   ? Set the value of the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\EnableSecurityFilters to 0 (zero).
   
6. Close Registry Editor.

For more information about how to troubleshoot networking issues that you may experience with Windows SBS 2003, click the following article number to view the article in the Microsoft Knowledge Base:
904946You experience intermittent communication failure between computers that are running Windows XP or Windows Server 2003
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For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:
912222 The Microsoft Windows Server 2003 Scalable Networking Pack release
927695 You cannot host TCP connections when Receive Side Scaling is enabled in Windows Server 2003 with Service Pack 2

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