Configuring Bgp Filtering By Neighbor - Cisco WS-CBS3032-DEL Software Configuration Manual

Chapter 39 Configuring IP Unicast Routing

Configuring BGP Filtering by Neighbor

You can filter BGP advertisements by using autonomous-system-path filters, such as the as-path
access-list global configuration command and the neighbor filter-list router configuration command.
You can also use access lists with the neighbor distribute-list router configuration command.
Distribute-list filters are applied to network numbers. See the
in Routing Updates" section on page 39-107
You can use route maps on a per-neighbor basis to filter updates and to modify various attributes. You
can apply a route map to either inbound or outbound updates. Only the routes that pass the route map
are sent or accepted in updates. On both inbound and outbound updates, matching is supported based on
autonomous-system path, community, and network numbers. Autonomous-system-path matching
requires the match as-path access-list route-map command, community-based matching requires the
match community-list route-map command, and network-based matching requires the ip access-list
global configuration command.
Beginning in privileged EXEC mode, follow these steps to apply a per-neighbor route map:
Command
Step 1
configure terminal
Step 2 router bgp autonomous-system
Step 3 neighbor {ip-address | peer-group name}
distribute-list {access-list-number | name}
{in | out}
Step 4
neighbor {ip-address | peer-group name}
route-map map-tag {in | out}
Step 5
end
Step 6 show ip bgp neighbors
Step 7 copy running-config startup-config
Use the no neighbor distribute-list command to remove the access list from the neighbor. Use the no
neighbor route-map map-tag router configuration command to remove the route map from the
neighbor.
OL-13270-06
for information about the distribute-list command.
Purpose
Enter global configuration mode.
Enable a BGP routing process, assign it an autonomous-system
number, and enter router configuration mode.
(Optional) Filter BGP routing updates to or from neighbors as
specified in an access list.
You can also use the neighbor prefix-list router
Note
configuration command to filter updates, but you cannot use
both commands to configure the same BGP peer.
(Optional) Apply a route map to filter an incoming or outgoing
route.
Return to privileged EXEC mode.
Verify the configuration.
(Optional) Save your entries in the configuration file.
Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
Configuring BGP
"Controlling Advertising and Processing
39-59