DOCUMENT:Q174095 03-JUN-2001 [win95x] TITLE :IGMP Query Times Out in Windows 95 with Winsock2 Update PRODUCT :Microsoft Windows 95.x Retail Product PROD/VER::2 OPER/SYS: KEYWORDS:kbfile kbnetwork kbtool win95 kbgraphxlinkcriticalkbfixlist ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows 95 - Microsoft Windows 95 OEM Service Release, version 2 ------------------------------------------------------------------------------- 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 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.