DOCUMENT:Q156441 17-DEC-2000 [crossnet] TITLE :NetBIOS Applications Stop Receiving Data Running on TCP/IP 32 PRODUCT :Windows for Workgroups and Windows NT Networking Issues PROD/VER: OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft TCP/IP-32 for Windows for Workgroups, versions 3.11, 3.11a, 3.11b ------------------------------------------------------------------------------- SYMPTOMS ======== NetBIOS applications running on Microsoft TCP/IP 32 for Windows For Workgroups may stop receiving data from server-side applications. The problem will only occur if the client pauses before receiving data for more than one NetBIOS Session KeepAlive interval. NOTE: The default NetBIOS Session KeepAlive interval for TCP/IP 32 is 60 minutes. CAUSE ===== The problem occurs because of the NetBIOS over TCP/IP Vxd's (VNBT) handling of Session KeepAlive packets when application data is also pending in TCP. If VNBT posts a receive for application data pending in TCP and a NetBIOS Session KeepAlive packet also resides in the TCP pending queue, VNBT would incorrectly determine the state of the lower TCP connection resulting in all future NetBIOS Receives being placed in a pending state. RESOLUTION ========== Vnbt.386 was modified to correctly handle NetBIOS KeepAlive packets in TCP's pending queue. STATUS ====== Microsoft has confirmed this to be a problem in TCP/IP 32 version 3.11B. A supported fix is now available, but is not fully regression tested and should be applied only to systems experiencing this specific problem. Contact Microsoft Product Support Services for more information. Additional query words: ====================================================================== Keywords : Technology : kbAudDeveloper kbTCPIPSearch kbZNotKeyword3 kbTCPIP311 kbTCPIP311a kbTCPIP311b Issue type : kbbug ============================================================================= 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.