Update that improves AD FS proxy and STS reliability in Windows Server 2012 R2 when multiple clients sign in

Assume that you have a Security Token Service (STS) installed on a Windows Server 2012 R2-based computer. When multiple clients (over 200 clients) try to sign in by using an Active Directory Federation Services (AD FS) proxy, the AD FS proxy consumes 100% usage of the CPU. In this situation, the AD FS proxy performance is slow, and causes a delay that exceeds 10seconds. This also causes STS to work under minimal load. Therefore, STS rejects the requests or serves only 5 to 10 requests per second.

This issue occurs because the additional "stale" requests are added to the request pool when multiple clients try to sign in. Therefore, the resource usage on AD FS is exhausted.

To resolve this issue, install update rollup 2955164, or install the hotfix that is described in this article.

Update information

For more information about how to obtain this update rollup package, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there is a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website: Note The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must first install the update 2919355 on Windows Server 2012 R2. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows Server 2012 R2 file information and notes

Important Windows 8.1 hotfixes and Windows Server 2012 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 8.1/Windows Server 2012 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.

• The files that apply to a specific product, milestone (RTM,SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
  Collapse this tableExpand this table

  Version	Product	Milestone	Service branch
  6.3.960 0.17xxx	Windows Server 2012 R2	RTM	GDR

• The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information" section. MUM, MANIFEST, and the associated security catalog (.cat) files, are very important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x64-based versions of Windows Server 2012 R2

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

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

Additional file information

Additional file information for Windows Server 2012 R2

Additional files for all supported x64-based versions of Windows Server 2012 R2