Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 149

Example of Assigning Sequence Numbers to Filters If you want to forward all routes that do not match the prefix list criteria, configure a prefix list filter to permit all routes (permit 0.0.0.0/0 le 32). The "permit all" filter must be the last filter in your prefix list. To permit the default route only, enter permit 0.0.0.0/0. The following example shows 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. Dell(conf-nprefixl)#seq 20 permit 0.0.0.0/0 le 32 Dell(conf-nprefixl)#seq 12 deny 134.23.0.0 /16 Dell(conf-nprefixl)#seq 15 deny 120.23.14.0 /8 le 16 Dell(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 Dell(conf-nprefixl)# NOTE: The last line in the prefix list Juba contains a "permit all" statement. By including this line in a prefix list, you specify that all routes not matching any criteria in the prefix list are forwarded. To delete a filter, use the no seq sequence-number command in PREFIX LIST mode. If you are creating a standard prefix list with only one or two filters, you can let the system assign a sequence number based on the order in which the filters are configured. The system assigns filters in multiples of five. Creating a Prefix List Without a Sequence Number To create a filter without a specified sequence number, use the following commands. 1 Create a prefix list and assign it a unique name. CONFIGURATION mode ip prefix-list prefix-name 2 Create a prefix list filter with a deny or permit action. CONFIG-NPREFIXL mode {deny | permit} ip-prefix [ge min-prefix-length] [le max-prefix-length] 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). Example of Creating a Filter with System-Assigned Sequence Numbers The example shows a prefix list in which the sequence numbers were assigned by the software. The filters were assigned sequence numbers based on the order in which they were configured (for example, the first filter was given the lowest sequence number). The show config command in PREFIX LIST mode displays the two filters with the sequence numbers 5 and 10. Dell(conf-nprefixl)#permit 123.23.0.0 /16 Dell(conf-nprefixl)#deny 133.24.56.0 /8 Dell(conf-nprefixl)#show conf Access Control Lists (ACLs) 149