Slow performance when you enable IPsec encryption on a specific TCP port number in Windows 7 or in Windows Server 2008 R2

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Article ID: 2665206 - View products that this article applies to.
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SYMPTOMS

Assume that you configure a connection security rule in Windows Firewall Advanced Security on a computer that is running Windows 7 or Windows Server 2008 R2. The connection security rule enables IPsec encryption on a specific outgoing TCP port number. In this situation, you experience a significant decrease in network performance. Additionally, many TCP packets are dropped in the TCP stack before they are sent to the remote system.

Note
 If you enable IPsec encryption for all traffic between computers, the issue does not occur.

For example, you experience this issue in the following scenario:
  • You have two computers that are running Windows 7 or Windows Server 2008 R2.
  • You create a port specific connection security rule in Windows Firewall Advanced Security.
  • You try to transfer files between the computers.
In this scenario, you experience slow performance.

CAUSE

This issue occurs because the TCP protocol uses the Large Send Offload (LSO) feature incorrectly when a port-specific rule is enabled. In this situation, the TCP protocol drops the frame internally and causes a retransmit scenario.

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=support
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 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 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:
    Collapse this tableExpand this table
    VersionProductMilestoneService branch
    6.1.760 0.21xxxWindows 7 and Windows Server 2008 R2RTMLDR
    6.1.760 1.21xxxWindows 7 and Windows Server 2008 R2SP1LDR
  • 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
Collapse this tableExpand this table
File nameFile versionFile sizeDateTime
Fwpkclnt.sys6.1.7600.21166187,24809-Mar-201214:14
Tcpip.sys6.1.7600.211661,303,40809-Mar-201214:15
Fwpkclnt.sys6.1.7601.21939187,76009-Mar-201213:57
Tcpip.sys6.1.7601.219391,306,48009-Mar-201213:58
For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
Collapse this tableExpand this table
File nameFile versionFile sizeDateTime
Fwpkclnt.sys6.1.7600.21166288,11209-Mar-201215:09
Tcpip.sys6.1.7600.211661,879,92009-Mar-201215:09
Fwpkclnt.sys6.1.7601.21939288,62409-Mar-201215:37
Tcpip.sys6.1.7601.219391,902,96009-Mar-201215:37
For all supported IA-64-based versions of Windows Server 2008 R2
Collapse this tableExpand this table
File nameFile versionFile sizeDateTime
Fwpkclnt.sys6.1.7600.21166482,67209-Mar-201214:07
Tcpip.sys6.1.7600.211663,807,60009-Mar-201214:07
Fwpkclnt.sys6.1.7601.21939483,18409-Mar-201213:57
Tcpip.sys6.1.7601.219393,814,76809-Mar-201213:58

WORKAROUND

To work around the issue, use one of the following methods:
  • If the network driver supports the Large Send Offload (LSO) feature, disable the feature on the network adapter.
    To disable the Large Send Offload feature, follow these steps:
    • Open Control Panel, and then click Network and Internet.
    • Click Network and Sharing Center.
    • In the left panel, click Change adapter settings.
    • Right-click the appropriate Local Area Connection, and then click Properties.
    • Click Configure.
    • On the Advanced tab, select the Large Send Offload option in the Property list, and then select Disabled in the Value field.
    Note Disable all separate options for the Large Send Offload feature for both IPv4 and IPv6.
  • Change the connection security rule to encrypt traffic on all ports between the two IP addresses.

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
Collapse this tableExpand this table
File nameX86_1c54f7bca69371f4dd9b2e48ef4fbded_31bf3856ad364e35_6.1.7600.21166_none_8b17e84ae78e476d.manifest
File versionNot applicable
File size702
Date (UTC)09-Mar-2012
Time (UTC)20:59
File nameX86_bab6acf273b8e758f569b7ca1fdf3db5_31bf3856ad364e35_6.1.7601.21939_none_c7a20d5483ba586e.manifest
File versionNot applicable
File size702
Date (UTC)09-Mar-2012
Time (UTC)20:59
File nameX86_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7600.21166_none_b39488e8e0c679d2.manifest
File versionNot applicable
File size3,834
Date (UTC)09-Mar-2012
Time (UTC)14:42
File nameX86_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.21939_none_b59e8054ddd1a7d5.manifest
File versionNot applicable
File size3,834
Date (UTC)09-Mar-2012
Time (UTC)14:26
Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
Collapse this tableExpand this table
File nameAmd64_376beac9f190c5060fdfe74e5ac05186_31bf3856ad364e35_6.1.7600.21166_none_61238e837a463399.manifest
File versionNot applicable
File size706
Date (UTC)09-Mar-2012
Time (UTC)20:59
File nameAmd64_64d50b5a9d799345128a3cc7ae755709_31bf3856ad364e35_6.1.7601.21939_none_8bfacaff3acafc00.manifest
File versionNot applicable
File size706
Date (UTC)09-Mar-2012
Time (UTC)20:59
File nameAmd64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7600.21166_none_0fb3246c9923eb08.manifest
File versionNot applicable
File size3,838
Date (UTC)09-Mar-2012
Time (UTC)15:41
File nameAmd64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.21939_none_11bd1bd8962f190b.manifest
File versionNot applicable
File size3,838
Date (UTC)09-Mar-2012
Time (UTC)16:07
Additional files for all supported IA-64-based versions of Windows Server 2008 R2
Collapse this tableExpand this table
File nameIa64_283a203d4a9f4d3bd672dea590baa08c_31bf3856ad364e35_6.1.7600.21166_none_fcb21df34905dfef.manifest
File versionNot applicable
File size704
Date (UTC)09-Mar-2012
Time (UTC)20:59
File nameIa64_4eb6fd295c4327f3eb4bf36375e12d1b_31bf3856ad364e35_6.1.7601.21939_none_1c665ce3bee2447b.manifest
File versionNot applicable
File size704
Date (UTC)09-Mar-2012
Time (UTC)20:59
File nameIa64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7600.21166_none_b3962cdee0c482ce.manifest
File versionNot applicable
File size3,836
Date (UTC)09-Mar-2012
Time (UTC)15:42
File nameIa64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.21939_none_b5a0244addcfb0d1.manifest
File versionNot applicable
File size3,836
Date (UTC)09-Mar-2012
Time (UTC)15:20

Properties

Article ID: 2665206 - Last Review: April 11, 2012 - Revision: 1.0
APPLIES TO
  • Windows Server 2008 R2 Enterprise
  • Windows Server 2008 R2 Datacenter
  • Windows Server 2008 R2 Standard
  • Windows Server 2008 R2 for Itanium-Based Systems
  • Windows Server 2008 R2 Foundation
  • Windows Web Server 2008 R2
  • Windows 7 Enterprise
  • Windows 7 Home Basic
  • Windows 7 Home Premium
  • Windows 7 Professional
  • Windows 7 Starter
  • Windows 7 Ultimate
Keywords: 
kbautohotfix kbqfe kbhotfixserver kbfix kbsurveynew kbexpertiseadvanced KB2665206

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