Symptoms

When you use the TCP receive window autotuning feature in a TCP connection, you notice that the feature only works for a while and then stops working. Additionally, you experience slow performance when a large amount of data is transferred over the connection.



Note This issue occurs when one of the following conditions is true:

  • A TCP¬†SYN packet is retransmitted more than one time over the TCP connection.

  • The TCP connection is created by a client that does not support the TCP window scaling feature. For example, the TCP connection is created by a computer that is running Windows XP.

Cause

This issue occurs because the TCP/IP driver disables the autotuning feature incorrectly for all the connections on the computer if an incoming connection does not support the autotuning feature or if a TCP SYN packet is retransmitted more than one time.

Note The expected behavior is that the autotuning feature is disabled on specific TCP connections on the computer instead of on all the connections on the computer.

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

There are no prerequisites.

Restart requirement

You may have to 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 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 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 R2 and for Windows 7" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely 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 7

File name

File version

File size

Date

Time

Platform

Fwpkclnt.sys

6.1.7600.16385

187,472

14-Jul-2009

01:20

x86

Tcpip.sys

6.1.7600.20712

1,288,576

12-May-2010

09:20

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

6.1.7600.16385

288,336

14-Jul-2009

01:47

x64

Tcpip.sys

6.1.7600.20712

1,889,664

12-May-2010

08:50

x64

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

File name

File version

File size

Date

Time

Platform

Fwpkclnt.sys

6.1.7600.16385

482,896

14-Jul-2009

01:58

IA-64

Tcpip.sys

6.1.7600.20712

3,778,440

12-May-2010

06:57

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

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

947239 Description of the Receive Window Auto-Tuning feature for HTTP traffic on Windows Vista-based computers

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

945322 Network communication may be slow when a Windows Vista-based computer connects to a network

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

Update.mum

File version

Not applicable

File size

1,674

Date (UTC)

13-May-2010

Time (UTC)

18:59

Platform

Not applicable

File name

X86_ebd19fff5b3defe86ccaa2bbbd949d6e_31bf3856ad364e35_6.1.7600.20712_none_c02715adeac581cb.manifest

File version

Not applicable

File size

702

Date (UTC)

13-May-2010

Time (UTC)

18:59

Platform

Not applicable

File name

X86_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7600.20712_none_b3c6b988e0a15e0a.manifest

File version

Not applicable

File size

3,780

Date (UTC)

13-May-2010

Time (UTC)

19:03

Platform

Not applicable

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

File name

Amd64_cb2ce9d4436bdf067ab305c3a291032c_31bf3856ad364e35_6.1.7600.20712_none_455c02d7df859b2b.manifest

File version

Not applicable

File size

706

Date (UTC)

13-May-2010

Time (UTC)

18:59

Platform

Not applicable

File name

Amd64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7600.20712_none_0fe5550c98fecf40.manifest

File version

Not applicable

File size

3,784

Date (UTC)

13-May-2010

Time (UTC)

19:05

Platform

Not applicable

File name

Update.mum

File version

Not applicable

File size

1,906

Date (UTC)

13-May-2010

Time (UTC)

18:59

Platform

Not applicable

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

File name

Ia64_4bacb1e8b3820ac444e4cc4a77260fe8_31bf3856ad364e35_6.1.7600.20712_none_db22fbd0994ca1df.manifest

File version

Not applicable

File size

704

Date (UTC)

13-May-2010

Time (UTC)

18:59

Platform

Not applicable

File name

Ia64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7600.20712_none_b3c85d7ee09f6706.manifest

File version

Not applicable

File size

3,782

Date (UTC)

13-May-2010

Time (UTC)

18:59

Platform

Not applicable

File name

Update.mum

File version

Not applicable

File size

1,684

Date (UTC)

13-May-2010

Time (UTC)

18:59

Platform

Not applicable

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

What affected your experience?

Thank you for your feedback!

×