Filtering Routes With Community Lists; Manipulating The Community Attribute - Dell S4048–ON Configuration Manual

Filtering Routes with Community Lists

To use an IP community list or IP extended community list to filter routes, you must apply a match community filter to a route map
and then apply that route map to a BGP neighbor or peer group.
1. Enter the ROUTE-MAP mode and assign a name to a route map.
CONFIGURATION mode
route-map map-name [permit | deny] [sequence-number]
2. Configure a match filter for all routes meeting the criteria in the IP community or IP extended community list.
CONFIG-ROUTE-MAP mode
match {community community-list-name [exact] | extcommunity extcommunity-list-name
[exact]}
3. Return to CONFIGURATION mode.
CONFIG-ROUTE-MAP mode
exit
4. Enter ROUTER BGP mode.
CONFIGURATION mode
router bgp as-number
AS-number: 0 to 65535 (2-Byte) or 1 to 4294967295 (4-Byte) or 0.1 to 65535.65535 (Dotted format)
5. Apply the route map to the neighbor or peer group's incoming or outgoing routes.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | peer-group-name} route-map map-name {in | out}
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.
To view which BGP routes meet an IP community or IP extended community list's criteria, use the show ip bgp {community-
list | extcommunity-list} command in EXEC Privilege mode.

Manipulating the COMMUNITY Attribute

In addition to permitting or denying routes based on the values of the COMMUNITY attributes, you can manipulate the
COMMUNITY attribute value and send the COMMUNITY attribute with the route information.
By default, Dell Networking OS does not send the COMMUNITY attribute.
To send the COMMUNITY attribute to BGP neighbors, use the following command.
• Enable the software to send the router's COMMUNITY attribute to the BGP neighbor or peer group specified.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | peer-group-name} send-community
To view the BGP configuration, use the show config command in CONFIGURATION ROUTER BGP mode.
If you want to remove or add a specific COMMUNITY number from a BGP path, you must create a route map with one or both of
the following statements in the route map. Then apply that route map to a BGP neighbor or peer group.
1. Enter ROUTE-MAP mode and assign a name to a route map.
CONFIGURATION mode
Border Gateway Protocol IPv4 (BGPv4)
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