Symptoms

Consider the following scenario. You enable the AuthNoEncap policy to handle large payloads in a network environment. Then, you perform a network operation on a computer that is running Windows 7 or Windows Server 2008 R2 in the network environment. In this scenario, you may experience a significant decrease in network performance.

Cause

This issue occurs because the TCP stack uses the IPsec slow path instead of the IPsec fast path when the TCP stack processes AuthNoEncap traffic.

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 Web site:

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, you must be running one of the following operating systems:

  • Windows 7

  • Windows 7 Service Pack 1 (SP1)

  • Windows Server 2008 R2

  • Windows Server 2008 R2 Service Pack 1 (SP1)

For more information about how to obtain a Windows 7 or Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

976932 Information about Service Pack 1 for Windows 7 and for Windows Server 2008 R2

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 7 and Windows Server 2008 R2 file information notes


Important Windows 7 hotfixes and Windows Server 2008 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 7/Windows Server 2008 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:

    Version

    Product

    Milestone

    Service branch

    6.1.760
    0.21xxx

    Windows 7 and Windows Server 2008 R2

    RTM

    LDR

    6.1.760
    1.21xxx

    Windows 7 and Windows Server 2008 R2

    SP1

    LDR

  • GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.

  • 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 7 and for Windows Server 2008 R2" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are critical to maintaining the state of the updated component. 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 7

File name

File version

File size

Date

Time

Platform

Fwpkclnt.sys

6.1.7600.21006

187,264

12-Jul-2011

04:34

x86

Tcpip.sys

6.1.7600.21006

1,301,376

12-Jul-2011

04:35

x86

Fwpkclnt.sys

6.1.7601.21768

187,776

12-Jul-2011

05:56

x86

Tcpip.sys

6.1.7601.21768

1,303,424

12-Jul-2011

05:56

x86

For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

File name

File version

File size

Date

Time

Platform

Fwpkclnt.sys

6.1.7600.21006

288,128

12-Jul-2011

05:33

x64

Tcpip.sys

6.1.7600.21006

1,888,128

12-Jul-2011

05:33

x64

Fwpkclnt.sys

6.1.7601.21768

288,640

12-Jul-2011

05:29

x64

Tcpip.sys

6.1.7601.21768

1,914,240

12-Jul-2011

05:29

x64

For all supported IA-64-based versions of Windows Server 2008 R2

File name

File version

File size

Date

Time

Platform

Fwpkclnt.sys

6.1.7600.21006

482,688

12-Jul-2011

04:15

IA-64

Tcpip.sys

6.1.7600.21006

3,800,448

12-Jul-2011

04:15

IA-64

Fwpkclnt.sys

6.1.7601.21768

483,200

12-Jul-2011

04:19

IA-64

Tcpip.sys

6.1.7601.21768

3,803,520

12-Jul-2011

04:19

IA-64

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 7 and for Windows Server 2008 R2

Additional files for all supported x86-based versions of Windows 7

File name

X86_63b2417eb9dd62e0eb1139be82c86eca_31bf3856ad364e35_6.1.7600.21006_none_5fee7b79ebde9cca.manifest

File version

Not applicable

File size

702

Date (UTC)

12-Jul-2011

Time (UTC)

09:21

Platform

Not applicable

File name

X86_a24ff779972a7e2a89a2bd8ffa8d1fe4_31bf3856ad364e35_6.1.7601.21768_none_4630e7eeeb8d371b.manifest

File version

Not applicable

File size

702

Date (UTC)

12-Jul-2011

Time (UTC)

09:21

Platform

Not applicable

File name

X86_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7600.21006_none_b3d5668ae095d505.manifest

File version

Not applicable

File size

3,834

Date (UTC)

12-Jul-2011

Time (UTC)

04:57

Platform

Not applicable

File name

X86_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.21768_none_b57d0c7addeae803.manifest

File version

Not applicable

File size

3,834

Date (UTC)

12-Jul-2011

Time (UTC)

06:20

Platform

Not applicable

Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

File name

Amd64_64de594551836357dfd1d976aeb0e347_31bf3856ad364e35_6.1.7601.21768_none_478f19f3354ca5a0.manifest

File version

Not applicable

File size

706

Date (UTC)

12-Jul-2011

Time (UTC)

09:21

Platform

Not applicable

File name

Amd64_e2ddea40f744287622ae42f8e4b38fc3_31bf3856ad364e35_6.1.7600.21006_none_131570faab66a0a9.manifest

File version

Not applicable

File size

706

Date (UTC)

12-Jul-2011

Time (UTC)

09:21

Platform

Not applicable

File name

Amd64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7600.21006_none_0ff4020e98f3463b.manifest

File version

Not applicable

File size

3,838

Date (UTC)

12-Jul-2011

Time (UTC)

05:59

Platform

Not applicable

File name

Amd64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.21768_none_119ba7fe96485939.manifest

File version

Not applicable

File size

3,838

Date (UTC)

12-Jul-2011

Time (UTC)

07:11

Platform

Not applicable

Additional files for all supported IA-64-based versions of Windows Server 2008 R2

File name

Ia64_0289f3c0cf5086b1b5f86369e0ba37f7_31bf3856ad364e35_6.1.7600.21006_none_4e515909ccd19c1a.manifest

File version

Not applicable

File size

704

Date (UTC)

12-Jul-2011

Time (UTC)

09:21

Platform

Not applicable

File name

Ia64_7558328428d6e0808c0f4aa357866d35_31bf3856ad364e35_6.1.7601.21768_none_c15e4cc30c7da21f.manifest

File version

Not applicable

File size

704

Date (UTC)

12-Jul-2011

Time (UTC)

09:21

Platform

Not applicable

File name

Ia64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7600.21006_none_b3d70a80e093de01.manifest

File version

Not applicable

File size

3,836

Date (UTC)

12-Jul-2011

Time (UTC)

05:55

Platform

Not applicable

File name

Ia64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.21768_none_b57eb070dde8f0ff.manifest

File version

Not applicable

File size

3,836

Date (UTC)

12-Jul-2011

Time (UTC)

07:02

Platform

Not applicable

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