Q228811: Socket Programs May Not Connect to Server

Article: Q228811
Product(s): Microsoft Windows NT
Version(s): winnt:4.0 SP4
Operating System(s): 
Keyword(s): kbnetwork kbWinNT400sp5fix
Last Modified: 18-NOV-2000

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The information in this article applies to:

- Microsoft Windows NT Server version 4.0 SP4 
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SYMPTOMS
========

After you install Windows NT 4.0 Service Pack 4 on your computer running Windows
NT, socket-based programs may stop responding (hang). A network trace may show
that the TCP/IP packets may not be ordered in the proper sequence.

CAUSE
=====

This behavior is caused by a change in the calculations for random Initial
Sequence Numbers (ISN) used in TCP/IP packets. As a result, an ISN may be
generated that is less than the current ISN and, as a result, TCP/IP packets may
be out of sequential order.

RESOLUTION
==========

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 the Microsoft products that are
listed at the beginning of this article. This problem was first corrected in
Windows NT version 4.0 Service Pack 5.

MORE INFORMATION
================

For additional information about random Initial Sequence Numbers, please see the
following article in the Microsoft Knowledge Base:

  Q192292 Unpredictable TCP Sequence Numbers in SP4


Additional query words:

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Keywords          : kbnetwork kbWinNT400sp5fix 
Technology        : kbWinNTsearch kbWinNT400xsearch kbWinNTSsearch kbWinNTS400sp4 kbWinNTS400xsearch
Version           : winnt:4.0 SP4
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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