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Q177656: Windows NT IP Router Loses Learned Routes

Article: Q177656
Product(s): Microsoft Windows NT
Version(s): WinNT:3.5,3.51,4.0
Operating System(s): 
Keyword(s): kb3rdparty kbinterop kbnetwork
Last Modified: 09-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Server versions 3.5, 3.51, 4.0 
- Microsoft Routing and Remote Access Service Update for Windows NT Server version 4.0 
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SYMPTOMS
========

Your Windows NT server that is running either Routing Information Protocol (RIP)
for IP or Routing and Remote Access Service (RRAS) may lose its routing table
after a few minutes. There are no event logs or other messages to indicate a
problem.

CAUSE
=====

The other routers with which your Windows NT router is communicating are sending
RIP v1 announcements to the "all zeros" subnet of the network instead of the
"all ones" subnet.

RESOLUTION
==========

To resolve this issue, you will need to configure your other routers to use an
"all ones" broadcast address. Please consult the documentation that came with
your routers for information on how to do this.


MORE INFORMATION
================

Traditionally the broadcast address to which a RIP v1 router sends its routing
table is the .255, or "all ones" subnet. With a network number of 191.23.107.0
the broadcast address would be 191.23.107.255, assuming normal subnetting. Some
older network operating systems use the .0, or "all zeros," subnet for their
broadcasts and those systems broadcast to an address that is identical to the
network number.

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Keywords          : kb3rdparty kbinterop kbnetwork 
Technology        : kbWinNTsearch kbWinNT351search kbWinNT350search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbWinNTS350 kbWinNTS351search kbWinNTS350search kbAudDeveloper kbRRASNTSearch kbRRASNT400
Version           : WinNT:3.5,3.51,4.0
Issue type        : kbprb

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