Network connection is slow when you run a WFP-based application on a computer that is running Windows 7 or Windows Server 2008 R2

Symptoms

Assume that you run an application that is developed by using Windows Filtering Platform (WFP) API on a computer that is running Windows 7 or Windows Server 2008 R2. When the application filters network traffic, the network connection is slow.

Cause

This issue occurs because the computer does not send TCP/IP ACK messages until a time-out occurs. This occurs when the driver for WFP filters data that the driver receives through the network. Therefore, the network traffic stalls the transfer of data when the TCP/IP ACK messages are delayed.

Resolution

Update information

How to obtain this update

Microsoft Update
This update is available from the Microsoft Update website:

Prerequisites

To apply this hotfix, you must be running Windows 7 Service Pack 1 (SP1) or 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

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
Properties

Article ID: 2735855 - Last Review: Oct 24, 2012 - Revision: 1

Windows 7 Enterprise, Windows 7 Home Basic, Windows 7 Home Premium, Windows 7 Professional, Windows 7 Starter, Windows 7 Ultimate, Windows Server 2008 R2 Datacenter, Windows Server 2008 R2 Enterprise, Windows Server 2008 R2 for Itanium-Based Systems, Windows Server 2008 R2 Foundation, Windows Server 2008 R2 Standard, Windows Web Server 2008 R2

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