Dell PowerSwitch S4820T 9.50.1 Configuration Guide for the S4820T System - Page 226

• If the prefix list contains no filters, all routes are permitted. • If none of the routes match any of the filters in the prefix list, the route is denied. This action is called an implicit deny. (If you want to forward all routes that do not match the prefix list criteria, you must configure a prefix list filter to permit all routes. For example, you could have the following filter as the last filter in your prefix list permit 0.0.0.0/0 le 32). • After a route matches a filter, the filter's action is applied. No additional filters are applied to the route. To view the BGP configuration, use the show config command in ROUTER BGP mode. To view a prefix list configuration, use the show ip prefix-list detail or show ip prefix-list summary commands in EXEC Privilege mode. Filtering BGP Routes Using Route Maps To filter routes using a route map, use these commands. 1. Create a route map and assign it a name. CONFIGURATION mode route-map map-name [permit | deny] [sequence-number] 2. Create multiple route map filters with a match or set action. CONFIG-ROUTE-MAP mode {match | set} For information about configuring route maps, refer to Access Control Lists (ACLs). 3. Return to CONFIGURATION mode. CONFIG-ROUTE-MAP mode exit 4. Enter ROUTER BGP mode. CONFIGURATION mode router bgp as-number 5. Filter routes based on the criteria in the configured route map. CONFIG-ROUTER-BGP mode neighbor {ip-address | peer-group-name} route-map map-name {in | out} Configure the following parameters: • ip-address or peer-group-name: enter the neighbor's IP address or the peer group's name. • map-name: enter the name of a configured route map. • in: apply the route map to inbound routes. • out: apply the route map to outbound routes. To view the BGP configuration, use the show config command in CONFIGURATION ROUTER BGP mode. To view a route map configuration, use the show route-map command in EXEC Privilege mode. 226 Border Gateway Protocol IPv4 (BGPv4)