Microsoft KB Archive/838408

= Network Load Balancing servers are removed from the Internet Group Management Protocol membership list in Windows Server 2003 =

Article ID: 838408

Article Last Modified on 7/24/2007

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APPLIES TO


 * Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)
 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Server 2003, Web Edition
 * Microsoft Windows Server 2003, 64-Bit Datacenter Edition
 * Microsoft Windows Server 2003, Enterprise x64 Edition

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SYMPTOMS
A computer that is a Network Load Balancing server and that is running Microsoft Windows Server 2003 and the Internet Group Management Protocol (IGMP) may not respond to IGMP queries from some multicast routers. This behavior may cause the Network Load Balancing server to be removed from the IGMP membership list.



CAUSE
This problem occurs because Network Load Balancing IGMP report messages are not synchronized with host membership queries from the router or from the switch. The IGMP stack that is used by the Network Load Balancing client is hard-coded to send a report message every 60 seconds. IEEE RFC 1112 specifies that the client software must respond to IGMP membership queries after a randomly selected delay that is not greater than 10 seconds. However, the Network Load Balancing report messages are not synchronized with the IGMP membership queries in Windows Server 2003. This scenario causes the router or the switch to drop the Network Load Balancing client from the membership list.



Hotfix information
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 do not have to restart your computer after you apply this hotfix.

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

File information
The English version of this hotfix has the file attributes (or later) 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.

Windows Server 2003, 64-Bit Edition
  Date         Time   Version            Size    File name --  06-May-2004  16:50  5.2.3790.170      381,952  Wlbs.sys

Windows Server 2003, 32-bit editions
  Date         Time   Version            Size    File name --  06-May-2004  20:00  5.2.3790.170      169,984  Wlbs.sys



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



WORKAROUND
To work around this problem, do not use IGMP. To avoid using IGMP, configure Virtual Local Area Networks (VLANs) to isolate Network Load Balancing traffic to a subset of ports on the switch. If you use this workaround, you must reconfigure both the switch and the Network Load Balancing nodes from IGMP multicast mode to unicast mode.

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

193602 Configuration options for WLBS hosts connected to layer 2 switches



MORE INFORMATION
For additional 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

Additional query words: v-lans Cisco Catalyst 6500 NLB

Keywords: kbqfe kbhotfixserver kbclustering kbserver kbnetwork kbwinserv2003presp1fix kbhardware kbinterop kbfix kbbug KB838408

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