Denial of Service Attack Possible with IPX/SPX Protocol

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Article ID: 265334 - View products that this article applies to.
This article was previously published under Q265334
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Under the following conditions, you computer may become unresponsive, or appear to stop responding (hang):
  • The Microsoft IPX/SPX protocol is installed on your computer.
  • You are connected to a network.


This problem can occur if your computer receives a denial of service attack that targets an IPX diagnostic port. This type of denial of service attack can generate large amounts of network traffic (a network storm) by using the Microsoft IPX/SPX protocol. A portion of the IPX/SPX protocol listens on the IPX diagnostic port and replies to requests for diagnostic information. The diagnostic port listener software does not filter the requesting computer's network address correctly, and may reply to a network broadcast address, which causes other IPX diagnostic listener programs to also reply. This may generate a large amount of unnecessary network traffic.


A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:
Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:
   Date      Time    Version     Size    File name     Platform
   08/03/00  04:38p  04.00.951   51,052  Nwlink.vxd  Windows 95
   08/03/00  04:38p  04.00.1114  51,567  Nwlink.vxd  Windows 95 OSR2
   06/30/00  06:47p  04.10.1999  51,034  Nwlink.vxd  Windows 98
   06/30/00  06:47p  04.10.2223  51,039  Nwlink.vxd  Windows 98 SE

To work around this problem, restart your computer.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

More information

For additional information about Windows 98 and Windows 98 Second Edition hotfixes, click the article number below to view the article in the Microsoft Knowledge Base:
206071 General Information About Windows 98 and Windows 98 Second Edition Hotfixes
For additional information about Windows 95 hotfixes, click the article number below to view the article in the Microsoft Knowledge Base:
161020 Implementing Windows 95 Updates


Article ID: 265334 - Last Review: November 3, 2013 - Revision: 2.0
Applies to
  • Microsoft Windows 95
kbnosurvey kbarchive kbhotfixserver kbqfe kbfix kbnetwork kbprb KB265334

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