Microsoft KB Archive/907717

= Windows Firewall may drop ICMP packets on a Windows XP SP2-based computer that has more than one network adapter =

Article ID: 907717

Article Last Modified on 8/29/2007

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APPLIES TO

 Microsoft Windows XP Service Pack 2, when used with:  Microsoft Windows XP Professional

 Microsoft Windows XP Home Edition 

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SYMPTOMS
You are using a Microsoft Windows XP Service Pack 2 (SP2)-based computer that has more than one network adapter. On this computer, Windows Firewall may drop Internet Control Message Protocol (ICMP) packets when ICMP is enabled in the firewall configuration. In this scenario, Windows Firewall drops the ICMP reply message. Additionally, information that is similar to the following appears in the firewall log:

DROP ICMP 169.168.25.1 10.10.1.1 - - 60 - - - - 0 0 - SEND



CAUSE
This problem occurs because an anti-spoofing rule drops packets if the following conditions are true:
 * A multi-homed computer receives an ICMP echo request on one network adapter.
 * The IP destination of the packet is the IP address of the other network adapter.



RESOLUTION
A supported hotfix is now 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 this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or 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. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Prerequisites
No prerequisites are required.

Restart requirement
You must restart the computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace any other hotfix.

File information
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

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STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.

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MORE INFORMATION
For more information about how to obtain a hotfix for Windows XP, click the following article number to view the article in the Microsoft Knowledge Base:

322389 How to obtain the latest Windows XP service pack

For more information, 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

Keywords: kbqfe kbhotfixserver kbwinxppresp3fix kbfix kbbug KB907717

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