SMB commands run serially when the SMB packet-signing feature is enabled in Windows 7 SP1 or in Windows Server 2008 R2 SP1

Symptoms

Assume that the server message block (SMB) packet-signing feature is enabled on a computer that is running Windows 7 Service Pack 1 (SP1) or Windows Server 2008 R2 Service Pack 1 (SP1). When you run an application that accesses multiple remote computers at the same time, the application runs the SMB commands serially, and Windows accesses the remote computers serially. Therefore, you may experience slow performance on the computer. 

Notes

  • This issue also occurs when the SMB redirector accesses only one SMB server.

  • This issue occurs only when you use SMB version 1.

  • The issue does not occur on a computer that is running Windows Server 2003, Windows XP, or Windows Vista. The SMB redirector on those operating systems uses TDI Transport instead of Winsock Kernel (WSK) Transport.

Cause

When the SMB packet-signing feature is enabled, the SMB redirector does not release the Security Signature resource until the SMB redirector receives an acknowledgement message that states the packet was sent successfully from the WSK Transport. However, the WSK Transport sends the acknowledgement message only when the WSK Transport receives an acknowledgement message from the server. Therefore, the SMB redirector processes network packets serially. 

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

  • Windows 7 Service Pack 1 (SP1)

  • 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 apply this hotfix, 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
    1.17xxx

    Windows 7 and Windows Server 2008 R2

    SP1

    GDR

    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

Mrxsmb.sys

6.1.7601.17796

123,904

17-Mar-2012

05:06

Mrxsmb.sys

6.1.7601.21946

123,904

17-Mar-2012

04:50

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

File name

File version

File size

Date

Time

Mrxsmb.sys

6.1.7601.17796

158,208

17-Mar-2012

05:10

Mrxsmb.sys

6.1.7601.21946

158,208

17-Mar-2012

05:13

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

File name

File version

File size

Date

Time

Mrxsmb.sys

6.1.7601.17796

367,616

17-Mar-2012

04:31

Mrxsmb.sys

6.1.7601.21946

368,128

17-Mar-2012

04:22

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 how to use the SMB packet signing feature, go to following Microsoft website:

General information about how to use the SMB packet signing featureFor 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_aaab76b76e19ba41769bc775b16a5ff9_31bf3856ad364e35_6.1.7601.17796_none_a11153fc4cf9f35e.manifest

File version

Not applicable

File size

698

Date (UTC)

17-Mar-2012

Time (UTC)

12:28

File name

X86_ebe407abf9d3d0620c5ac1ed59b6488d_31bf3856ad364e35_6.1.7601.21946_none_8afdb5aa2ba598d6.manifest

File version

Not applicable

File size

698

Date (UTC)

17-Mar-2012

Time (UTC)

12:28

File name

X86_microsoft-windows-smbminirdr_31bf3856ad364e35_6.1.7601.17796_none_81445c20af9e94b2.manifest

File version

Not applicable

File size

4,757

Date (UTC)

17-Mar-2012

Time (UTC)

07:49

File name

X86_microsoft-windows-smbminirdr_31bf3856ad364e35_6.1.7601.21946_none_82040a6dc893a5ee.manifest

File version

Not applicable

File size

4,757

Date (UTC)

17-Mar-2012

Time (UTC)

07:25

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

File name

Amd64_1610e7536ae3266eef763301e1480034_31bf3856ad364e35_6.1.7601.17796_none_d88a43fe7682e398.manifest

File version

Not applicable

File size

702

Date (UTC)

17-Mar-2012

Time (UTC)

12:28

File name

Amd64_9a285824c1754cd74171172b50205ea6_31bf3856ad364e35_6.1.7601.21946_none_74a327c8a709e12c.manifest

File version

Not applicable

File size

702

Date (UTC)

17-Mar-2012

Time (UTC)

12:28

File name

Amd64_microsoft-windows-smbminirdr_31bf3856ad364e35_6.1.7601.17796_none_dd62f7a467fc05e8.manifest

File version

Not applicable

File size

4,761

Date (UTC)

17-Mar-2012

Time (UTC)

08:38

File name

Amd64_microsoft-windows-smbminirdr_31bf3856ad364e35_6.1.7601.21946_none_de22a5f180f11724.manifest

File version

Not applicable

File size

4,761

Date (UTC)

17-Mar-2012

Time (UTC)

08:30

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

File name

Ia64_1958f5869b3786c4c88941f13e7375b3_31bf3856ad364e35_6.1.7601.21946_none_ea36d9cacac87231.manifest

File version

Not applicable

File size

700

Date (UTC)

17-Mar-2012

Time (UTC)

12:28

File name

Ia64_4363f47e3b14e4f37353e84e9e7ec276_31bf3856ad364e35_6.1.7601.17796_none_0e4cc5805519b676.manifest

File version

Not applicable

File size

700

Date (UTC)

17-Mar-2012

Time (UTC)

12:28

File name

Ia64_microsoft-windows-smbminirdr_31bf3856ad364e35_6.1.7601.17796_none_81460016af9c9dae.manifest

File version

Not applicable

File size

4,759

Date (UTC)

17-Mar-2012

Time (UTC)

08:36

File name

Ia64_microsoft-windows-smbminirdr_31bf3856ad364e35_6.1.7601.21946_none_8205ae63c891aeea.manifest

File version

Not applicable

File size

4,759

Date (UTC)

17-Mar-2012

Time (UTC)

08:16

Need more help?

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

Was this information helpful?

Thank you for your feedback!

×