Policies and Filters

Syntax

Use the following CLI commands or Web management interface panels to configure BGP4 community filters.

Table C.22: BGP4 Community Filters

CLI syntax

Web management links

 

 

HP9300(config-bgp-router)# community-filter <filter-num> permit

Configure->BGP->Community Filter

deny <num> internet no-advertise no-export

 

HP9300(config-bgp-routemap RMAP_NAME)# match

Configure->BGP->Route Map Filter

as-path-filters community-filters address-filters <num,num,...>

 

[metric <num>] [next-hop <ip-addr>]

 

[route-type internal external-type1 external-type2]

 

[tag <tag-value>]

 

 

 

NOTE: The match command compares the information you configure for the command’s parameters against BGP routes. You use this command when configuring a route map. If the comparison matches a route, set statements in the route map specify the action to take. See “Defining Route Maps” on page 10-59.

Redistribution Filters

Redistribution filters control the exchange of routes between routing protocols. IP/RIP, OSPF, and BGP4 support redistribution of one another’s routes. In addition, they all allow exchange of static routes.

You configure IP/RIP and OSPF redistribution filters to permit or deny routes for specific network addresses. Optionally, you can also filter on and modify the route metric. To configure redistribution, you configure redistribution filters in the protocol that will receive the routes. Redistribution is disabled by default in RIP and OSPF and enabled by default in BGP4.

BGP4 redistribution filters can filter based on a route’s metric, weight, and also on the results of comparison of the route information with a route map. A route map is a named set of match conditions and parameter settings that a routing switch can use to modify route attributes and to control redistribution of routes. For more information, see “Defining Route Maps” on page 10-59.

BGP4 allows you to include the redistribution filters as part of a route map. A route map examines and modifies route information exchanged between BGP4 and IP/RIP or OSPF. See “Configuring BGP4” on page 10-1for more information.

Figure D.7 shows an example of a redistribution filter. In this example, redistribution filters in OSPF are configured to redistribute two RIP routes into OSPF. Notice that unlike some other filter examples in this appendix, a filter for permitting all routes (to change the default action) is not configured. To maintain tight control over redistribution, the default action “deny any” is allowed to remain. Only routes that explicitly match the permit filters are permitted to be redistributed. Thus, in Figure D.7, the RIP route to 191.47.12.0/24 is not redistributed because there is no “permit any” filter that changes the default action from deny to permit.

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