You cannot connect to a Windows 2000-based virtual private network (VPN) server if one or more of the network routers do not support packet fragmentation

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You cannot make virtual private network (VPN) connections to a Microsoft Windows 2000-based VPN server if one or more of the network routers do not support packet fragmentation. In this situation, you find that many packets are dropped if you perform network diagnostics to monitor the network.
The problem occurs because the Maximum Receive Unit (MRU) value in Windows 2000 is hard-coded to 1500 bytes. VPN connections add some extra bytes to the packet headers. This may cause the packet size to exceed the maximum MRU that the router allows. If one or more of the routers do not support packet fragmentation, the packets will be dropped. Therefore, the VPN connection will fail.
After you apply this hotfix, the MRU is determined through negotiation with remote computers.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.


No prerequisites are required.

Restart requirement

You must restart your computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
File nameFile versionFile sizeDateTimePlatform
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
More information
For more information about how hotfix packages are named, click the following article number to view the article in the Microsoft Knowledge Base:
816915 New file naming schema for Microsoft Windows software update packages
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates
pptp, l2tp, rras

Article ID: 887372 - Last Review: 11/02/2013 17:54:00 - Revision: 3.0

Microsoft Windows 2000 Professional Edition, Microsoft Windows 2000 Server, Microsoft Windows 2000 Advanced Server

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