You experience poor performance when you use Kerberos authentication to connect to lots of remote computers at the same time from a computer that is running Windows Server 2008 or Windows Vista

Symptoms

Consider the following scenario:

  • You have a computer that is running Windows Server 2008 or Windows Vista.

  • You use Kerberos authentication to connect to lots of remote computers at the same time.

In this scenario, you experience the following issues on the computer:

  • Unexpectedly high CPU usage in the Lsass.exe process

  • Poor Kerberos authentication performance

Cause

These issues occur because the Kerberos client unnecessarily performs a time-consuming computation at the pre-authentication stage. When there are many concurrent remote connections, you experience high CPU usage in the Lsass.exe process.

Resolution

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 the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

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, contact 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:

http://support.microsoft.com/contactus/?ws=supportNote 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, your computer must be running Windows Server 2008 Service Pack 2 (SP2) or Windows Vista Service Pack 2 (SP2).

For more information about how to obtain a Windows Server 2008 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

968849 How to obtain the latest service pack for Windows Server 2008

For more information about how to obtain a Windows Vista service pack, click the following article number to view the article in the Microsoft Knowledge Base:

935791 How to obtain the latest Windows Vista service pack

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 English (United States) 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 2008 and Windows Vista file information notes

Important Windows Vista hotfixes and Windows Server 2008 hotfixes are included in the same packages. However, only "Windows Vista" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows Vista" 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, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.

    Version

    Product

    SR_Level

    Service branch

    6.0.600
    2.
    22xxx

    Windows Server 2008 and Windows Vista

    SP2

    LDR

  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 and for Windows Vista" section. MUM files and MANIFEST files, 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 x86-based versions of Windows Server 2008 and of Windows Vista

File name

File version

File size

Date

Time

Platform

Kerberos.dll

6.0.6002.22469

500,736

18-Aug-2010

16:57

x86

For all supported x64-based versions of Windows Server 2008 and of Windows Vista

File name

File version

File size

Date

Time

Platform

Kerberos.dll

6.0.6002.22469

658,944

18-Aug-2010

17:27

x64

Kerberos.dll

6.0.6002.22469

500,736

18-Aug-2010

16:57

x86

For all supported IA-64-based versions of Windows Server 2008

File name

File version

File size

Date

Time

Platform

Kerberos.dll

6.0.6002.22469

1,396,224

18-Aug-2010

16:47

IA-64

Kerberos.dll

6.0.6002.22469

500,736

18-Aug-2010

16:57

x86

Status

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

More Information

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

Additional file information

Additional file information for Windows Vista and for Windows Server 2008

Additional files for all supported x86-based versions of Windows Vista and of Windows Server 2008

File name

Update.mum

File version

Not Applicable

File size

3,078

Date (UTC)

18-Aug-2010

Time (UTC)

22:25

Platform

Not Applicable

File name

X86_2400bd15a0c7cc1265c1a12d79a1aae4_31bf3856ad364e35_6.0.6002.22469_none_42aa73f999a6eb94.manifest

File version

Not Applicable

File size

705

Date (UTC)

18-Aug-2010

Time (UTC)

22:25

Platform

Not Applicable

File name

X86_microsoft-windows-security-kerberos_31bf3856ad364e35_6.0.6002.22469_none_e90f1a54c739ff85.manifest

File version

Not Applicable

File size

38,326

Date (UTC)

18-Aug-2010

Time (UTC)

17:17

Platform

Not Applicable

Additional files for all supported x64-based versions of Windows Vista and of Windows Server 2008

File name

Amd64_a7b703961524228be0f316a61f39751a_31bf3856ad364e35_6.0.6002.22469_none_fe7c74d5446cd1ec.manifest

File version

Not Applicable

File size

1,060

Date (UTC)

18-Aug-2010

Time (UTC)

22:25

Platform

Not Applicable

File name

Amd64_microsoft-windows-security-kerberos_31bf3856ad364e35_6.0.6002.22469_none_452db5d87f9770bb.manifest

File version

Not Applicable

File size

38,362

Date (UTC)

18-Aug-2010

Time (UTC)

17:50

Platform

Not Applicable

File name

Update.mum

File version

Not Applicable

File size

3,102

Date (UTC)

18-Aug-2010

Time (UTC)

22:25

Platform

Not Applicable

File name

Wow64_microsoft-windows-security-kerberos_31bf3856ad364e35_6.0.6002.22469_none_4f82602ab3f832b6.manifest

File version

Not Applicable

File size

38,939

Date (UTC)

18-Aug-2010

Time (UTC)

17:04

Platform

Not Applicable

Additional files for all supported IA-64-based versions of Windows Server 2008

File name

Ia64_1f2e952b6da913faccf6aca2c92b591d_31bf3856ad364e35_6.0.6002.22469_none_0227cb5ce21dbef3.manifest

File version

Not Applicable

File size

1,058

Date (UTC)

18-Aug-2010

Time (UTC)

22:25

Platform

Not Applicable

File name

Ia64_microsoft-windows-security-kerberos_31bf3856ad364e35_6.0.6002.22469_none_e910be4ac7380881.manifest

File version

Not Applicable

File size

38,344

Date (UTC)

18-Aug-2010

Time (UTC)

17:06

Platform

Not Applicable

File name

Update.mum

File version

Not Applicable

File size

2,255

Date (UTC)

18-Aug-2010

Time (UTC)

22:25

Platform

Not Applicable

File name

Wow64_microsoft-windows-security-kerberos_31bf3856ad364e35_6.0.6002.22469_none_4f82602ab3f832b6.manifest

File version

Not Applicable

File size

38,939

Date (UTC)

18-Aug-2010

Time (UTC)

17:04

Platform

Not Applicable

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