WEBVTT

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Two Cisco routers share a transit link and use different autonomous system numbers.

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Configure each neighbor with the address and autonomous system number of its peer.

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Router two advertises two loopbacks, and the summary shows both prefixes received.

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The curved line shows the established BGP session over TCP.

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Shut down the BGP neighbor and check that the transit link still responds.

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Bring the neighbor back up and verify that both routes return.

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Before filtering, ping each remote loopback to confirm both are reachable.

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Create a prefix list that denies one loopback and permits the remaining prefixes.

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Apply that list to an inbound route map for the BGP neighbor.

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The session stays established, but the denied route disappears from the routing table.

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Ping both loopbacks again to see how the policy changes reachability.

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Remove the deny entry and confirm that the route and ping return.