Dell Force10 E600i FTOS Version 8.4.1.5 Configuration Guide for ExaScale - Page 151

Configuration Task List for Prefix Lists To configure a prefix list, you must use commands in the PREFIX LIST, the ROUTER RIP, ROUTER OSPF, and ROUTER BGP modes. Basically, you create the prefix list in the PREFIX LIST mode, and assign that list to commands in the ROUTER RIP, ROUTER OSPF and ROUTER BGP modes. The following list includes the configuration tasks for prefix lists: • Configure a prefix list • Use a prefix list for route redistribution For a complete listing of all commands related to prefix lists, refer to the FTOS Command Line Interface Reference document. Configure a prefix list To configure a prefix list, use these commands in the following sequence, starting in the CONFIGURATION mode: Step Command Syntax 1 ip prefix-list prefix-name Command Mode CONFIGURATION 2 seq sequence-number CONFIG-NPREFIXL {deny | permit} ip-prefix [ge min-prefix-length] [le max-prefix-length] Purpose Create a prefix list and assign it a unique name. You are in the PREFIX LIST mode. Create a prefix list with a sequence number and a deny or permit action. The optional parameters are: • ge min-prefix-length: is the minimum prefix length to be matched (0 to 32). • le max-prefix-length: is the maximum prefix length to be matched (0 to 32). If you want to forward all routes that do not match the prefix list criteria, you must configure a prefix list filter to permit all routes (permit 0.0.0.0/0 le 32). The "permit all" filter should be the last filter in your prefix list. To permit the default route only, enter permit 0.0.0.0/0. The following example illustrates how the seq command orders the filters according to the sequence number assigned. In the example, filter 20 was configured before filter 15 and 12, but the show config command displays the filters in the correct order. FTOS(conf-nprefixl)#seq 20 permit 0.0.0.0/0 le 32 FTOS(conf-nprefixl)#seq 12 deny 134.23.0.0 /16 FTOS(conf-nprefixl)#seq 15 deny 120.23.14.0 /8 le 16 FTOS(conf-nprefixl)#show config ! ip prefix-list juba seq 12 deny 134.23.0.0/16 seq 15 deny 120.0.0.0/8 le 16 seq 20 permit 0.0.0.0/0 le 32 FTOS(conf-nprefixl)# IP Access Control Lists (ACL), Prefix Lists, and Route-maps | 151