Microsoft KB Archive/167395

= If RouteTimeOut Is Set to a Value Lower Than the Default of 180 Seconds, Routes May Expire Prematurely =

Article ID: 167395

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Server 4.0, Terminal Server Edition
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 4.0 Standard Edition

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This article was previously published under Q167395



IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.



SYMPTOMS
Routes may appear in the route table as having a metric of 16. A Routing Information Protocol (RIP) route with a metric of 16 is defined as "unreachable." This can cause difficulties with connectivity to remote resources or can cause connections to use another router.



CAUSE
There is a problem in Iprip.dll that causes route entries to expire, thus causing routes to time out early. Additionally, for very low values of RouteTimeOut, it may still be necessary to make a registry change to prevent early route expiration, as described here.

For more information on RouteTimeOut, please see the following article in the Microsoft Knowledge Base:

ARTICLE-ID: 169161

TITLE : Registry Parameters for RIP for IP version 1



RESOLUTION
To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

152734 How to Obtain the Latest Windows NT 4.0 Service Pack

After applying the hotfix, if you have modified the RouteTimeOut registry value to time out routes in less than the default value of 180 seconds, it may be necessary to adjust the granularity of the timeout routine. This can be accomplished with the new MaxTimedOpsInterval registry parameter, as follows:

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.  Start Registry Editor (Regedt32.exe). Go to the following subkey in the registry:

NOTE: The above registry key is one path; it has been wrapped for readability.  Click Edit, click Add Value and then enter the following information:

     Parameter Type: REG_DWORD Default:       10 (seconds) Range:         1-0xffffffff Description:   This registry value sets the maximum amount of time allowed between invocations of the routine that performs route maintenance. In effect, it controls the granularity of the amount of time that can be                     decremented from each route's expiration time. It                     should be set to a value less than the difference between RouteTimeOut and the RIP announcement interval. Microsoft does not recommend setting the parameter to any value greater than the default of 10 seconds.  Exit Registry Editor.

For example, if you set the RouteTimeOut value to its minimum of 20 seconds and your router(s) sends RIP announcements every 15 seconds, this value should be set to 4 seconds or less.

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STATUS
Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.

Additional query words: poison route timeout sixteen

Keywords: kbhotfixserver kbqfe kbbug kbfix kbqfe KB167395

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