DOCUMENT:Q258875 19-NOV-2000 [winnt] TITLE :BUG: Win2000 Multicast Groups Not Rejoined When Interface Enable PRODUCT :Microsoft Windows NT PROD/VER::2000 OPER/SYS: KEYWORDS:kbnetwork kbAPI kbOSWin2000 kbOSWin2000bug kbSDKPlatform kbSDKWin32 kbWinsock kbDSuppor ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows 2000 Advanced Server - Microsoft Windows 2000 Server - Microsoft Windows 2000 Professional ------------------------------------------------------------------------------- SYMPTOMS ======== When an interface is disabled and then re-enabled in Windows 2000 either by the user interface or through MediaSense, if the adapter was joined to multicast groups, the interface may not be able to receive multicasts from those groups once it is re-enabled. Internet Group Membership Protocol (IGMP) should be sending a join message for each group that the computer is a member of when the interface is re-enabled. CAUSE ===== This problem occurs when the multicast sockets are bound to INADDR_ANY. Mulicast groups are rejoined as expected if the socket is bound to a specific interface. RESOLUTION ========== Workaround ---------- A well written application should generally monitor for address changes and should unjoin and then rejoin the multicast group when there is an address change (especially when obtaining a different IP address). You can use the SIO_ADDRESS_LIST_CHANGE option of the WSAIoctl function to receive notification of an address list change. STATUS ====== Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article. REFERENCES ========== For additional information, click the article number below to view the article in the Microsoft Knowledge Base: Q131978 HOWTO: Receive/Send Multicasts Under WinNT/Win95 Using WinSock See the "Windows Sockets 2 API Programmer's Reference in the Platform SDK" at the following Web site: http://msdn.microsoft.com/library Additional query words: IGMP ====================================================================== Keywords : kbnetwork kbAPI kbOSWin2000 kbOSWin2000bug kbSDKPlatform kbSDKWin32 kbWinsock kbDSupport kbGrpDSNet Technology : kbwin2000AdvServ kbwin2000AdvServSearch kbwin2000Serv kbwin2000ServSearch kbwin2000Search kbwin2000ProSearch kbwin2000Pro kbWinAdvServSearch Version : :2000 Issue type : kbbug Solution Type : kbpending ============================================================================= 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 2000.