Windows NT IP Router Loses Learned Routes

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This article was previously published under Q177656

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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.

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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.

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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.

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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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