Administrator Guide

CONFIG-PREFIX LIST mode
exit
4 Enter ROUTER BGP mode.
CONFIGURATION mode
router bgp as-number
5 Filter routes based on the criteria in the congured prex list.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | peer-group-name} distribute-list prefix-list-name {in | out}
Congure the following parameters:
• ip-address or peer-group-name: enter the neighbor’s IP address or the peer group’s name.
• prefix-list-name: enter the name of a congured prex list.
• in: apply the prex list to inbound routes.
• out: apply the prex list to outbound routes.
As a reminder, the following are rules concerning prex lists:
• If the prex list contains no lters, all routes are permitted.
• If none of the routes match any of the lters in the prex list, the route is denied. This action is called an implicit deny. (If you want to
forward all routes that do not match the prex list criteria, you must congure a prex list lter to permit all routes. For example, you
could have the following lter as the last lter in your prex list permit 0.0.0.0/0 le 32).
• After a route matches a lter, the lter’s action is applied. No additional lters are applied to the route.
To view the BGP conguration, use the show config command in ROUTER BGP mode. To view a prex list conguration, 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 lter 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 lters with a match or set action.
CONFIG-ROUTE-MAP mode
{match | set}
For information about conguring 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 congured route map.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | peer-group-name} route-map map-name {in | out}
204
Border Gateway Protocol IPv4 (BGPv4)