DOCUMENT:Q181350 10-AUG-2001 [winnt] TITLE :Clients Fail to Connect to Notes Server Running on Windows NT PRODUCT :Microsoft Windows NT PROD/VER:WinNT:3.5,3.51,4.0 OPER/SYS: KEYWORDS:kb3rdparty kbnetwork ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server versions 3.5, 3.51, 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== You have Lotus Notes server software running on your computer running Windows NT Server. Your Lotus Notes clients may experience difficulty connecting to this Lotus Notes server for periods of time up to five minutes. A network packet capture reveals that the client connection attempts are being refused by a Transmission Control Protocol (TCP) reset from the server. CAUSE ===== Lotus Notes Server programmatically binds a backlog queue of five to Winsock. RESOLUTION ========== Lotus Development Corporation has produced a fix that increases the size of the backlog queue to the maximum under Windows NT Server. Please contact Lotus Notes technical support for more information regarding this fix. Lotus Notes is manufactured by Lotus Development Corporation, a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this products' performance or reliability. For information about how to contact Lotus Development Corporation, query in the Knowledge Base for one of the following articles: ARTICLE-ID: Q65416 TITLE : Hardware and Software Third-Party Vendor Contact List, A-K ARTICLE-ID: Q60781 TITLE : Hardware and Software Third-Party Vendor Contact List, L-P ARTICLE-ID: Q60782 TITLE : Hardware and Software Third-Party Vendor Contact List, Q-Z MORE INFORMATION ================ The issue appears when a large number of users try to connect to the Lotus Notes server at the same time. The Winsock backlog queue fills up because of the time it takes for the server to service the request and the hundreds of new requests that are continually being attempted. This problem has only been reported in large enterprise environments and has been reproduced on a Lotus Notes 4.x server but may affect earlier versions as well. For additional information on TCP/IP, please see the following white paper available on the Microsoft anonymous ftp server: File Name: Tcpipimp2.doc Location : ftp://ftp.microsoft.com/bussys/winnt/winnt-docs/papers/ Title : "Microsoft Windows NT 3.5/3.51/4.0: TCP/IP Implementation Details TCP/IP Protocol Stack and Services, Version 2.0" ====================================================================== Keywords : kb3rdparty kbnetwork Technology : kbWinNTsearch kbWinNT351search kbWinNT350search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbWinNTS350 kbWinNTS351search kbWinNTS350search Version : WinNT:3.5,3.51,4.0 Issue type : kbprb ============================================================================= 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.