DOCUMENT:Q254930 08-MAY-2002 [winnt] TITLE :TCP Session with Server Never Closes PRODUCT :Microsoft Windows NT PROD/VER::4.0 OPER/SYS: KEYWORDS:kbWinNT400PreSP7Fix kbbpqfe1a ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 4.0 - Microsoft Windows NT Workstation version 4.0 - Microsoft Windows NT Server version 4.0, Terminal Server Edition ------------------------------------------------------------------------------- SYMPTOMS ======== A TCP session with a server may seem never to close, even though the client has requested to close the session. For example, a connection is established between two Windows NT-based computers. The server application quits, and the server sends a FIN request (which the network loses). The server state is now FIN_WAIT_1 or LAST_ACK and the client state is ESTABLISHED. The server will remain in the FIN_WAIT or last_ack state until a reboot is issued to restore incoming sessions. RESOLUTION ========== Windows NT Server and Workstation --------------------------------- A supported fix is now available from Microsoft, but it is only intended to correct the problem described in this article and should be applied only to systems experiencing this specific problem. This fix may receive additional testing at a later time, to further ensure product quality. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows NT 4.0 service pack that contains this fix. To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, please go to the following address on the World Wide Web: http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS NOTE: In special cases, charges that are normally incurred for support calls may be canceled, if a Microsoft Support Professional determines that a specific update will resolve your problem. Normal support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The English-language version of this fix should have the following file attributes or later: Date Time Size File name Platform ------------------------------------------------- 02/16/2000 08:01p 171,728 Tcpip.sys Intel 02/16/2000 08:00p 305,840 Tcpip.sys Alpha Windows NT Server, Terminal Server Edition ------------------------------------------ A supported fix is now available from Microsoft, but it is only intended to correct the problem described in this article and should be applied only to systems experiencing this specific problem. This fix may receive additional testing at a later time, to further ensure product quality. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows NT Server 4.0, Terminal Server Edition, service pack that contains this fix. To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, please go to the following address on the World Wide Web: http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS NOTE: In special cases, charges that are normally incurred for support calls may be canceled, if a Microsoft Support Professional determines that a specific update will resolve your problem. Normal support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The English-language version of this fix should have the following file attributes or later: Date Time Size File name Platform ------------------------------------------------- 09/26/2000 04:48p 174,544 Tcpip.sys Intel 09/26/2000 04:33p 311,024 Tcpip.sys Alpha STATUS ====== Windows NT Server and Workstation --------------------------------- Microsoft has confirmed this to be a problem in the Microsoft products that are listed at the beginning of this article. Windows NT Server, Terminal Server Edition ------------------------------------------ Microsoft has confirmed this to be a problem in the Microsoft products that are listed at the beginning of this article. MORE INFORMATION ================ When the client initiates the close of a session, it sends a FIN packet to the server. If the FIN packet is lost and never reaches the server, the client should retransmit the FIN packet when it does not receive an ACK response for the FIN packet. If the client does not retransmit the FIN packet, the server session does not close and orphans the session. The server will remain in the FIN_WAIT or last_ack state until a reboot is issued to restore incoming sessions. Example of a servers netstat -an: TCP nj031fpsb01:nbsession NC031LLAB03.wcc.microsoft.com:1094 LAST_ACK TCP nj031fpsb01:nbsession NC031LLAB03.wcc.microsoft.com:1096 LAST_ACK TCP nj031fpsb01:nbsession NC031LLAB03.wcc.microsoft.com:1097 LAST_ACK Refer to the Microsoft Developer Network (MSDN) for more information about FIN WAIT states and TCP state diagrams. Additional query words: FIN_WAIT last_ack Filenet win2000hotnet netlogon 5719 ====================================================================== Keywords : kbWinNT400PreSP7Fix kbbpqfe1a Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbNTTermServ400 kbNTTermServSearch Version : :4.0 Hardware : ALPHA x86 Issue type : kbbug Solution Type : kbfix ============================================================================= 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 2002.