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Q174095: IGMP Query Times Out in Windows 95 with Winsock2 Update

Article: Q174095
Product(s): Microsoft Windows 95.x Retail Product
Version(s): 2
Operating System(s): 
Keyword(s): kbfile kbnetwork kbtool win95 kbgraphxlinkcriticalkbfixlist
Last Modified: 03-JUN-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Windows 95 
- Microsoft Windows 95 OEM Service Release, version 2 
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SYMPTOMS
========

On a Windows 95-based computer with the Winsock2 Update for Windows 95
installed, IGMP queries may time out prematurely. This may result in computers
that are members of a multicast group being dropped from group membership.

CAUSE
=====

The TCP/IP driver in the Winsock2 Update for Windows 95 does not properly
implement the Max Response Time field as documented in the IGMP version 2 draft.
This behavior may cause clients participating in a multicast group to not
respond to IGMP requests from a router within the timeout period. When this
occurs, the router no longer forwards multicast packets to the expired group
member.

STATUS
======

This issue is resolved by the following updated file for Windows 95 and Windows
95 OEM Service Release 2 (OSR2):

  Vip.386 version 4.10.1512 (dated 7/29/97) and later

To install this update, use the following steps.

NOTE: This update should be applied only to Windows 95-based computers on which
the Winsock2 Update has been installed.

1. Download the Vipup20.exe file from the Microsoft Download Center to an empty
  folder.

2. In My Computer or Windows Explorer, double-click the Vipup20.exe file you
  downloaded in step 1.

3. Follow the instructions on the screen.

The following file is available for download from the Microsoft Download Center:

  Download Vipup20.exe now
  (http://download.microsoft.com/download/win95upg/update3/1/w95/EN-US/vipup20.exe)

For additional information about how to download Microsoft Support files, click
the article number below to view the article in the Microsoft Knowledge Base:

  Q119591 How to Obtain Microsoft Support Files from Online Services

Microsoft used the most current virus detection software available on the date of
posting to scan this file for viruses. Once posted, the file is housed on secure
servers that prevent any unauthorized changes to the file.

The following files are installed by Vipup20.exe:

  File name     Version    Date/Time        Size     Destination folder
  ---------------------------------------------------------------------
  Vip.386       4.10.1512  7/29/97 3:12p    71,754   Windows\System

MORE INFORMATION
================

The Winsock2 Update for Windows 95 is included in the Winsock2 Software
Development Kit (SDK), available from the following location on the Microsoft
FTP site:

  ftp://ftp.microsoft.com/bussys/winsock/winsock2

This issue is known to occur with the Vip.386 file version 4.10.1423 included in
the Ws295sdk.exe file dated 6/23/97 from the FTP location listed above. Future
revisions to this package may not exhibit this symptom.

Additional query words:

======================================================================
Keywords          : kbfile kbnetwork kbtool win95 kbgraphxlinkcritical kbfixlist
Technology        : kbWin95search kbOPKSearch kbZNotKeyword3 kbWin95OPKOSR2
Version           : :2

=============================================================================

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