Configuring Bgp Filtering With Route Maps; Configuring Bgp Filtering By Neighbor - Cisco Catalyst 3750-E Software Configuration Manual

Chapter 40 Configuring IP Unicast Routing
Command
Step 14
show ip bgp
show ip bgp neighbors
Step 15
copy running-config startup-config
Use the no form of each command to return to the default state.

Configuring BGP Filtering with Route Maps

Within BGP, route maps can be used to control and to modify routing information and to define the
conditions by which routes are redistributed between routing domains. See the
Redistribute Routing Information" section on page 40-94
route map has a name that identifies the route map (map tag) and an optional sequence number.
Beginning in privileged EXEC mode, follow these steps to use a route map to disable next-hop
processing:
Command
Step 1 configure terminal
Step 2 route-map map-tag [[permit | deny] |
sequence-number]]
Step 3 set ip next-hop ip-address [...ip-address]
[peer-address]
Step 4 end
Step 5 show route-map [map-name]
Step 6 copy running-config startup-config
Use the no route-map map-tag command to delete the route map. Use the no set ip next-hop ip-address
command to re-enable next-hop processing.

Configuring BGP Filtering by Neighbor

You can filter BGP advertisements by using AS-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
section on page 40-102
You can use route maps on a per-neighbor basis to filter updates and to modify various attributes. A route
map can be applied 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 AS
OL-9775-08
Purpose
Verify the reset by checking information about the routing
table and about BGP neighbors.
(Optional) Save your entries in the configuration file.
Purpose
Enter global configuration mode.
Create a route map, and enter route-map configuration mode.
(Optional) Set a route map to disable next-hop processing
In an inbound route map, set the next hop of matching routes to
•
be the neighbor peering address, overriding third-party next hops.
In an outbound route map of a BGP peer, set the next hop to the
•
peering address of the local router, disabling the next-hop
calculation.
Return to privileged EXEC mode.
Display all route maps configured or only the one specified to verify
configuration.
(Optional) Save your entries in the configuration file.
"Controlling Advertising and Processing in Routing Updates"
for information about the distribute-list command.
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
"Using Route Maps to
for more information about route maps. Each
Configuring BGP
40-55