Dell S4048T-ON, Configuration Manual

Page: 216 / 1146

• 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, see 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.
Filtering BGP Routes Using AS-PATH Information
To filter routes based on AS-PATH information, use these commands.
1 Create a AS-PATH ACL and assign it a name.
CONFIGURATION mode
216 Border Gateway Protocol IPv4 (BGPv4)