DOCUMENT:Q154174
PRODUCT: Microsoft Windows NT and Windows 95
TITLE: Windows NT and Win95 may hang when they receive invalid ICMP 
       datagram fragments
PROD/VER:4.00
OPER/SYS:WINDOWS
KEYWORDS:kbbug4.00 kbfile kbfix4.00 kbfix4.00.sp4 NTSrvWkst nttcp ssping 

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The information in this article applies to:

 - Microsoft Windows NT Workstation version 4.0
 - Microsoft Windows NT Server version 4.0
 - Microsoft Windows 95 

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SYMPTOMS
========

Windows NT and Windows 95 systems may hang when they receive corrupted ICMP 
datagram fragments from a client.


RESOLUTION
==========

Microsoft has updated the TCP/IP protocol stack to correct the problem. 
Instructions for installing it are available from Microsoft support channels, 
or directly from the Internet locations below.

Windows NT 4.0 SP3
------------------

NOTE: Service pack 3 must be applied to Windows NT 4.0 prior to applying
this fix.

This hotfix has been posted to the following Internet location:

   ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/
   hotfixes-postSP3/icmp-fix


Windows 95
-----------

This issue is resolved by the following updated file for Windows 95 and OSR2:

       VIP.386 version 4.0.956 (6/30/97) and later

This file is included in the self-extracting VIPUPD.EXE file.

To install this update, follow these steps:

1. Download the VIPUPD.EXE file from the online service listed below to
   an empty folder.

2. In My Computer or Windows Explorer, double-click the VIPUPD.EXE file
   you downloaded in step 1.

3. Follow the instructions on the screen.

The following file(s) are available for download from the Microsoft
Software Library:

 ~ VIPUPD.EXE

For more information about downloading files from the Microsoft Software
Library, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q119591
   TITLE     : How to Obtain Microsoft Support Files from Online Services


The following files are installed by VIPUPD.EXE:

   File name     Version    Date/Time        Size     Destination folder
   ----------------------------------------------------------------------
      VIP.386    4.00.956   6/30/97 9:54am   171,672  Windows\System


STATUS
======

Microsoft has confirmed this to be a problem in Windows NT version 4.0 
and Windows 95.  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.

Additional query words: prodnt 4.00 win95

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