Dell PowerSwitch S4112F-ON OS10 Enterprise Edition User Guide Release 10.4.1.0 - Page 600

For example, in 112.24.0.0/16, the first 16 bits of the address 112.24.0.0 match all addresses between 112.24.0.0 to 112.24.255.255. Use permit or deny filters for specific routes with the le (less or equal) and ge (greater or equal) parameters, where x.x.x.x/x represents a route prefix: • To deny only /8 prefixes, enter deny x.x.x.x/x ge 8 le 8 • To permit routes with the mask greater than /8 but less than /12, enter permit x.x.x.x/x ge 8 le 12 • To deny routes with a mask less than /24, enter deny x.x.x.x/x le 24 • To permit routes with a mask greater than /20, enter permit x.x.x.x/x ge 20 The following rules apply to prefix-lists: • A prefix-list without permit or deny filters allows all routes • An "implicit deny" is assumed - the route drops for all route prefixes that do not match a permit or deny filter • After a route matches a filter, the filter's action applies and no additional filters apply to the route Use prefix-lists in processing routes for routing protocols such as OSPF, RTM, and BGP. To configure a prefix-list, use commands in PREFIX-LIST and ROUTER-BGP modes. Create the prefix-list in PREFIX-LIST mode and assign that list to commands in ROUTER-BGP modes. Route-maps Route-maps a series of commands that contain a matching criterion and action. They change the packets meeting the matching criterion. ACLs and prefix-lists can only drop or forward the packet or traffic while route-maps process routes for route redistribution. For example, use a route-map to filter only specific routes and to add a metric. • Route-maps also have an implicit deny. Unlike ACLs and prefix-lists where the packet or traffic is dropped, if a route does not match the route-map conditions, the route is not redistributed. • Route-maps process routes for route redistribution. For example, to add a metric, a route-map can filter only specific routes. If the route does not match the conditions, the route-map decides where the packet or traffic drops. The route is not redistributed if it does not match. • Route-maps use commands to decide what to do with traffic. To remove the match criteria in a route-map, use the no match command. • In a BGP route-map, if you repeat the same match statements; for example, a match metric, with different values in the same sequence number, only the last match and set values are taken into account. Configure match metric OS10(config)# route-map hello OS10(conf-route-map)# match metric 20 View route-map OS10(conf-route-map)# do show route-map route-map hello, permit, sequence 10 Match clauses: metric 20 Change match OS10(conf-route-map)# match metric 30 View updated route-map OS10(conf-route-map)# do show route-map route-map hello, permit, sequence 10 Match clauses: metric 30 600 Access Control Lists