Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 148

• An "implicit deny" is assumed (that is, the route is dropped) for all route prefixes that do not match a permit or deny filter in a configured prefix list. • After a route matches a filter, the filter's action is applied. No additional filters are applied to the route. Implementation Information Prefix lists are used in processing routes for routing protocols (for example, router information protocol [RIP], open shortest path first [OSPF], and border gateway protocol [BGP]). NOTE: It is important to know which protocol your system supports prior to implementing prefix-lists. Configuration Task List for Prefix Lists To configure a prefix list, use commands in PREFIX LIST, ROUTER RIP, ROUTER OSPF, and ROUTER BGP modes. Create the prefix list in PREFIX LIST mode and assign that list to commands in ROUTER RIP, ROUTER OSPF and ROUTER BGP modes. The following list includes the configuration tasks for prefix lists, as described in the following sections. • Configuring a prefix list • Use a prefix list for route redistribution For a complete listing of all commands related to prefix lists, refer to the Dell Networking OS Command Line Reference Guide. Creating a Prefix List To create a prefix list, use the following commands. 1 Create a prefix list and assign it a unique name. You are in PREFIX LIST mode. CONFIGURATION mode ip prefix-list prefix-name 2 Create a prefix list with a sequence number and a deny or permit action. CONFIG-NPREFIXL mode seq sequence-number {deny | permit} ip-prefix [ge min-prefix-length] [le maxprefix-length] The optional parameters are: • ge min-prefix-length: the minimum prefix length to match (from 0 to 32). • le max-prefix-length: the maximum prefix length to match (from 0 to 32). Access Control Lists (ACLs) 148