Apply a BGP4 Extended Community Filter

You can apply an extended community filter to a neighbor through a route map.

Before you begin

Define a BGP4 Extended Community Filter.

Procedure

Access global configuration mode.
```
device# configure terminal
```
Define the matching conditions for the extended community.
```
device(config)# ip extcommunity-list 1 permit rt 123:2
```
This example specifies that community list 1 permits routes from network 2 in autonomous system 123.
Access BGP configuration mode.
```
device(config)# router bgp
```
Specify the autonomous system in which your device resides.
```
device(config-bgp-router)# local-as 1000
```
Specify the autonomous system in which the remote neighbor resides.
```
device(config-bgp-router)# neighbor 10.1.2.3 remote-as 1001
```

Access IPv4 address family configuration mode.

device(config-bgp-router)# address-family ipv4 unicast

Enable the exchange of information with the neighbor.
```
device(config-bgp-ipv4u)# neighbor 10.1.2.3 activate
```
Apply a route map to incoming routes.
```
device(config-bgp-ipv4u)# neighbor 10.1.2.3 route-map in extComRmapt 
```
This example uses the in keyword to apply route map extComRmapt.
Apply a route map to outgoing routes.
```
device(config-bgp-ipv4u)# neighbor 10.1.2.3 route-map out sendExtComRmap 
```
This example uses the out keyword to apply route map sendExtComRmap.
Enable the sending of standard and extended attributes in updates to the specified BGP neighbor.
```
device(config-bgp-ipv4u)# neighbor 10.1.2.3 send-community both
```
This example uses the send-community both keywords.

Example

The following example summarizes the commands in this procedure.

device# configure terminal
device(config)# ip extcommunity-list 1 permit rt 123:2
device(config)# router bgp
device(config-bgp-router)# local-as 1000
device(config-bgp-router)# neighbor 10.1.2.3 remote-as 1001
device(config-bgp-router)# address-family ipv4 unicast
device(config-bgp-ipv4u)# neighbor 10.1.2.3 activate
device(config-bgp-ipv4u)# neighbor 10.1.2.3 route-map in extComRmapt 
device(config-bgp-ipv4u)# neighbor 10.1.2.3 route-map out sendExtComRmap 
device(config-bgp-ipv4u)# neighbor 10.1.2.3 send-community both