Microsoft KB Archive/899657

= Windows Firewall may drop ICMP packets in Windows Server 2003 with Service Pack 1 (SP1) =

Article ID: 899657

Article Last Modified on 10/11/2007

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APPLIES TO

 Microsoft Windows Server 2003 SP1, when used with:  Microsoft Windows Server 2003, Standard Edition (32-bit x86)

 Microsoft Windows Server 2003, Web Edition

 Microsoft Windows Server 2003, Enterprise Edition

 Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems</li></ul>

 Microsoft Windows Server 2003, Standard x64 Edition</li></ul>

 Microsoft Windows Server 2003, Enterprise x64 Edition</li></ul> </li></ul>

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<div class="notice_section">

<div class="symptoms_section">

SYMPTOMS
On a computer that is running Microsoft Windows Server 2003 with Service Pack 1 (SP1), Windows Firewall may drop Internet Control Message Protocol (ICMP) packets, even though ICMP is enabled in the firewall configuration. For example, this problem may occur on a multihomed computer under the following conditions:
 * The computer receives an ICMP echo request on the NIC1 network adaptor.
 * The IP destination of the packet is the IP address of the NIC2 network adaptor.

When this problem occurs, information that is similar to the following appears in the firewall log: <pre class="fixed_text">2005-04-12 11:45:50 DROP ICMP 169.168.25.1 10.10.1.1 - - 60 - - - - 0 0 - SEND

<div class="cause_section">

CAUSE
This problem occurs because an anti-spoofing rule drops packets whose source IP address is bound to a different adaptor than the adaptor to which the ICMP packets are sent.

<div class="resolution_section">

Service pack information
To resolve this problem, obtain the latest service pack for Windows Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

889100 How to obtain the latest service pack for Windows Server 2003

Prerequisites
To apply this hotfix, you must have Windows Server 2003 Service Pack 1 installed.

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.

Microsoft Windows Server 2003, 32-bit versions
<pre class="fixed_text">  Date         Time   Version        Size     File name -  14-May-2005  00:35  5.2.3790.2444  102,912  Ipnat.sys

Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems
<pre class="fixed_text">  Date         Time   Version        Size     File name -  16-May-2005  01:42  5.2.3790.2444  349,696  Ipnat.sys

Microsoft Windows Server 2003, x64-based versions
<pre class="fixed_text">  Date         Time   Version        Size     File name -  16-May-2005  01:42  5.2.3790.2444  155,648  Ipnat.sys

<div class="status_section">

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

This problem was first corrected in Windows Server 2003 Service Pack 2.

<div class="moreinformation_section">

MORE INFORMATION
For more information about the terminology that is used in this article, 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 query words: Networking & Communications

Keywords: kbbug kbfix kbqfe kbpubtypekc kbhotfixserver KB899657

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