AS-Path Filtering practice labs

AS-Path Filtering: Accept Only Neighbor’s Own Routes

Advanced CCNP BGP policy lab focusing on inbound AS-path filtering at the edge. You will build a simple eBGP chain (AS 65003 — AS 65002 — AS 65001), originate prefixes from the two upstream routers, confirm that the edge learns multiple routes, then enforce a policy on the edge (R1) to accept only routes originated by its directly connected eBGP neighbor (AS 65002) while rejecting routes that transited AS 65003. Verification relies entirely on R1’s BGP table and AS-path regular-expression queries.