DOCUMENT:Q217207 04-APR-2002 [winnt] TITLE :Type of Service Octet in IP Header Not Initialized on Alpha PRODUCT :Microsoft Windows NT PROD/VER::4.0 SP4 OPER/SYS: KEYWORDS:kbnetwork kbWinNT400sp5fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 4.0 SP4 - Microsoft Windows NT Workstation version 4.0 SP4 ------------------------------------------------------------------------------- SYMPTOMS ======== The Type of Service (TOS) octet is not initialized to zero for Windows NT 4.0 Service Pack 4 and later builds on the Alpha and x86 platforms. This results in a random value for the Precedence field in the TOS octet. Some third-party vendor's TCP/IP stacks may require that the Precedence field be set to zero, and they will send a reset to any host that does not meet this requirement, thus causing sessions between Windows NT and such hosts to fail unless the Precedence field happens to get randomly initialized to zero on Windows NT. RESOLUTION ========== To work around this problem, statically start the TOS octet by setting the DefaultTOS value in the registry to some non-zero value. For additional information about how to modify the DefaultTOS value, please see the following article(s) in the Microsoft Knowledge Base: Q120642 TCP/IP and NBT Configuration Parameters for Windows 2000 or Windows NT To resolve this problem, obtain the latest service pack for Windows NT 4.0. For additional information, please see the following article in the Microsoft Knowledge Base: Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack STATUS ====== Microsoft has confirmed this to be a problem in Window NT 4.0. This problem was first corrected in Windows NT version 4.0 Service Pack 5. MORE INFORMATION ================ IBM mainframe hosts are IP hosts that are known to have this problem. The IP stack configuration on IBM mainframes can be configured to accept nonzero values in the Precedence field. Please see your IBM operating system documentation for information on how to make the necessary changes. The third-party products discussed in this article are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability. REFERENCES ========== Additional information is available in the following RFCs: - RFC 791, Internet Protocol -- DARPA Internet Program Protocol Specification - RFC 1349, Type of Service in the Internet Protocol Suite Additional query words: ====================================================================== Keywords : kbnetwork kbWinNT400sp5fix Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400search kbWinNT400search kbWinNTW400sp4 kbWinNTSsearch kbWinNTS400sp4 kbWinNTS400search Version : :4.0 SP4 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 2002.