DOCUMENT:Q165005 TITLE :Windows NT Slows Down Due to Land Attack PRODUCT :Microsoft Windows NT PROD/VER:4.00 OPER/SYS:WINDOWS KEYWORDS:kbbug kbbug4.00 kbenv kbfix4.00 kbpatch NTSrvWkst nttcp -------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Workstation version 4.0 - Microsoft Windows NT Server version 4.0 - Microsoft Windows NT Server Enterprise Edition version 4.0 -------------------------------------------------------------------------- SYMPTOMS ======== After receiving spoofed connection request (SYN) packets, Windows NT may begin to operate slowly. After about one minute, Windows NT returns to normal operation. NOTE: This problem may occur with TCP/IP on other operating systems as well. CAUSE ===== This behavior occurs due to "Land Attack". Land Attack sends SYN packets with the same source and destination IP addresses and the same source and destination ports to a host computer. This makes it appear as if the host computer sent the packet to itself. Windows NT operates more slowly while the host computer tries to respond to itself. RESOLUTION ========== To resolve this problem, obtain the following fix or wait for the next Windows NT service pack. This fix should have the following time stamp: 11/25/97 04:54p 143,472 Tcpip.sys (Intel) 11/25/97 04:52p 263,375 Tcpip.sys (Alpha) This hotfix has been posted to the following Internet location: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/ hotfixes-postSP3/land-fix/ NOTE: This fix supercedes the ICMP-fix, OOB-fix, and the Simptcp-fix hotfixes. STATUS ====== Microsoft has confirmed this to be a problem in Windows NT version 4.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information. MORE INFORMATION ================ For information on the hotfix for Windows 95, please see the following article in the Microsoft Knowledge Base: ARTICLE-ID: Q177539 TITLE : Windows 95 Stops Responding Because of Land Attack Additional query words: 4.00 port 139 ============================================================================ 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.
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