You publish a trunk on a server that is running Microsoft Forefront Unified Access Gateway (UAG) 2010.
You publish an Outlook Web Access application on the trunk.
The Outlook Web Access application is set as the initial application on the trunk.
The trunk is also set to use the Outlook Web Access theme.
You install security update 2649261 on the server that is running Forefront UAG 2010.
You access the trunk and then log on from a web browser.
In this scenario, you may be redirected to an error page instead of to the Outlook Web Access application.
After you install the security update, Forefront UAG performs a hash operation on the URL. This action triggers a redirect to an incorrect URL. The incorrect URL violates the built-in URL filtering rules and causes the redirect to the error page.
To resolve this problem, install the service pack that is described in the following Microsoft Knowledge Base article:
2710791 Description of Service Pack 2 for Forefront Unified Access Gateway 2010
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about security update 2649261, click the following article number to view the article in the Microsoft Knowledge Base:
2649261 MS12-026: Description of the security update for Microsoft Forefront Unified Access Gateway 2010 Service Pack 1: April 10, 2012
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates