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Q217207: Type of Service Octet in IP Header Not Initialized on Alpha

Article: Q217207
Product(s): Microsoft Windows NT
Version(s): 4.0 SP4
Operating System(s): 
Keyword(s): kbnetwork kbWinNT400sp5fix
Last Modified: 04-APR-2002

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The information in this article applies to:

- Microsoft Windows NT Server version 4.0 SP4 
- Microsoft Windows NT Workstation version 4.0 SP4 
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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

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