DOCUMENT:Q230177  16-MAY-2002  [winnt]
TITLE   :Corrupted Data Packet Causes PPTP to Hang in Ndiswan.sys
PRODUCT :Microsoft Windows NT
PROD/VER:winnt:4.0
OPER/SYS:
KEYWORDS:kbWinNT400sp5fix

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The information in this article applies to:

 - Microsoft Windows NT Server version 4.0 
 - Microsoft Windows NT Server, Enterprise Edition version 4.0 
 - Microsoft Windows NT Workstation version 4.0 
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SYMPTOMS
========

It is possible for a corrupted IP packet received over PPTP to cause your system
to bugcheck. This problem only occurs when you run PPTP.


CAUSE
=====

This problem is caused by a corrupted datapacket, where the Frame Length given
in the packet header was longer than expected. This caused the code that read
that frame to be confused and to corrupt memory, which in turn lead the computer
to stop responding (hang). The fix verifies that the Frame Length provided in a
packet is not larger than the system expects. Microsoft believes this error to
be rare, and the fix to be safe.

RESOLUTION
==========

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or
the individual software update. For information on obtaining the latest service
pack, please go to:

 - http://www.microsoft.com/windows/servicepacks/

-or-

 - Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack

For information on obtaining the individual software update, contact Microsoft
Product Support Services. For a complete list of Microsoft Product Support
Services phone numbers and information on support costs, please go to the
following address on the World Wide Web:

   http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS


STATUS
======

Microsoft has confirmed this to be a problem in Windows NT 4.0. This problem was
first corrected in Windows NT 4.0 Service Pack 5.

Additional query words:

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Keywords          : kbWinNT400sp5fix 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400 kbWinNTS400search kbWinNTS400
Version           : winnt:4.0
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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