FIX: Issues may occur when you deploy an ASP.NET 2.0-based application that communicates with Exchange Server when a SharePoint site is running IIS 7.0 or IIS 7.5 in Integrated mode

Symptoms

You deploy a Microsoft ASP.NET 2.0-based web application to a website that is hosted on a Microsoft Office SharePoint server. The web application communicates with Microsoft Exchange Server 2010. Additionally, you have Internet Information Services (IIS) 7.0 or IIS 7.5 running in Integrated mode on the SharePoint server. In this situation, you may encounter the following issues.

Issue 1

When you deploy a partially trusted Web Part on a SharePoint site, you may find that the Web Part may unexpectedly be able to perform Full Trust operations.

Issue 2

The Requests Queued performance counter in an ASP.NET performance object functions incorrectly in Integrated mode. For example, when the MaxConcurrentRequestsPerCPU setting is set too low, queuing is not reflected in the counter. Additionally, when the setting is set too high, queuing requests may be denied. This issue may decrease the performance of the SharePoint site.

Cause

Issue 1

This issue occurs because of an error in the ASP.NET 2.0 authentication component. The error causes the partially trusted Web Parts to impersonate the application pool account. Therefore, the Web Parts have full permission to access the SharePoint site.

Issue 2

This issue occurs because the ASP.NET\Request Queued performance counter only reports values when a request is queued in the ASP.NET Queue. It does not count the requests that are waiting for the common language runtime (CLR) thread pool.

Resolution

Issue 1

This hotfix adds a new application setting (aspnet:AllowAnonymousImpersonation) in ASP.NET 2.0. To enable this setting, add the following section to the Web.config file:

<appSettings>

<add key="aspnet:AllowAnonymousImpersonation" value="true" /></appSettings>To enable this setting, you must have IIS 7 or IIS 7.5 running in Integrated mode. When this setting is enabled, the application runs under the security context of the IUSR identity.

Issue 2

When you monitor the ASP.NET\Request Queued performance counter after you apply this hotfix, you see the values increase for the same application under the same load. This occurs because the ASP.NET\Request Queued performance counter counts both the requests that are queued in the ASP.NET Queue and the requests that are waiting for the CLR thread pool.

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

References

For more information about the options that you can use to deploy SharePoint Web Parts, visit the following Microsoft TechNet website:

Configure and deploy Web Parts (SharePoint Server 2010)For more information about performance counters for ASP.NET, visit the following Microsoft Developer Network (MSDN) website:

Performance Counters for ASP.NETFor more information about the ASP.NET\Request Queued performance counter issue, visit the following Microsoft website:

"ASP.NET\Requests Queued" bug in IIS integrated ModeFor 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