HP 7102dl - ProCurve Secure Router Configuration Manual page 821

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Table 15-12. Policies for BGP Communities
Community
internet
local-as
no-advertise
no-export
For example, your router connects to an external BGP neighbor. You configure
a community list to allow the router to advertise routes in the Internet
community, but to suppress advertisement of routes in the local AS. Enter
these commands:
ProCurve(config-comm-list)# permit internet
ProCurve(config-comm-list)# deny local-as no-advertise no-export
After configuring the community list, create a route map entry:
ProCurve(config)# route-map ISPOut 10
Then enter this command:
Syntax: match community <listname>
This command does not define a community for routes. It selects routes
according to their predefined community or communities. Other BGP neigh-
bors, either internal or external, should have placed the route in a community.
If you want to set other policies for the community, you must enter a set
command as described in "Prepending Private AS Numbers for Load Balanc-
ing" on page 15-99 and "Setting a Multi-Exit Discriminator Metric for Load
Balancing" on page 15-100. Otherwise, you should now apply the map to the
BGP neighbor as an outbound policy. (See "Applying a Route Map Entry to a
BGP Neighbor" on page 15-106.)
Filtering Advertised Routes According to AS Path. You can also filter
an advertised route according to the hops listed in its AS field. In this way, you
can attempt to influence which autonomous systems external neighbors can
access. For example, ISP routers can filter routes with paths that include
customer AS numbers to prevent themselves from advertising private cus-
tomer routes to unauthorized peers.
IP Routing—Configuring RIP, OSPF, BGP, and PBR
Advertise To
all peers
peers in the local AS
no peers
internal peers only
Configuring BGP
15-95