Dynamic Host Routes Are Not Removed if EnablePMTUDiscovery Is Set to Zero (326926)


The information in this article applies to:

  • Microsoft Windows 2000 Server
  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional
This article was previously published under Q326926

SYMPTOMS

Host routes may be dynamically added to your Windows 2000 routing table but may not ever be removed. The following registry key may have a EnablePMTUDiscover value of zero:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\TCPIP\Parameters\

CAUSE

A host route is added to the Windows 2000 routing table if an ICMP redirect is received from the default gateway. Windows 2000 typically removes the host route after 10 minutes. However, if EnablePMTUDiscover has a value of zero, Windows 2000 never removes the host routes.

RESOLUTION

Service Pack Information

To resolve this problem, obtain the latest service pack for Microsoft Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910 How to Obtain the Latest Windows 2000 Service Pack

Hotfix Information

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows 2000 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

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

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 typical 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 has the file attributes (or later) 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 tool in Control Panel.
   Date         Time   Version           Size     File name
   -----------------------------------------------------------
   19-Nov-2001  20:42  5.0.2195.4667     118,896  Afd.sys
   23-Jul-2002  18:17  5.0.2195.4874     105,232  Msafd.dll        
   21-Jun-2002  14:09  5.2.2.10            3,584  Spmsg.dll        
   21-Jun-2002  14:10  5.2.2.10           44,544  Spuninst.exe     
   13-Jun-2001  02:05  5.0.2195.3727       3,856  Svcpack1.dll     
   23-Jul-2002  18:08  5.0.2195.5964     313,200  Tcpip.sys
   31-Jul-2001  00:15  5.0.2195.3988      16,240  Tdi.sys
   23-Jul-2002  18:17  5.0.2195.4874      17,680  Wshtcpip.dll     
   21-Jun-2002  14:10  5.2.2.10           10,240  Spcustom.dll

After you apply this hotfix, Windows 2000 deletes the host routes after 10 minutes.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Microsoft Windows 2000 Service Pack 4.

MORE INFORMATION

For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:

265173 The Datacenter Program and Windows 2000 Datacenter Server Product

For additional information about how to install multiple hotfixes with only one reboot, click the article number below to view the article in the Microsoft Knowledge Base:

296861 Use QChain.exe to Install Multiple Hotfixes with One Reboot

For additional information about ICMP redirects, click the article number below to view the article in the Microsoft Knowledge Base:

195686 Explanation of ICMP Redirect Behavior

Modification Type:MinorLast Reviewed:10/5/2005
Keywords:kbHotfixServer kbQFE kbWin2kSP4fix kbbug kbenv kbfix kbWin2000PreSP3Fix kbWin2000preSP4Fix kbWin2000sp3fix kbNetwork KB326926
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