FTOS Configuration Guide for the C-Series - Force10 Networks

Filter routes
To filter routes, use prefix lists. OSPF applies prefix lists to incoming or outgoing routes. Incoming routes
must meet the conditions of the prefix lists, and if they do not, OSPF does not add the route to the routing
table. Configure the prefix list in CONFIGURATION PREFIX LIST mode prior to assigning it to the
OSPF process.
Command Syntax Command Mode Usage
ip prefix-list prefix-name CONFIGURATION Create a prefix list and assign it a unique
name. You are in PREFIX LIST mode.
seq sequence-number {deny |permit}
ip-prefix [ge min-prefix-length] [le
max-prefix-length]
CONFIG- PREFIX
LIST
For configuration information on prefix lists, refer to Chapter 13, IP Access Control Lists, Prefix Lists,
and Route-maps, on page 247.
Use the following commands in CONFIGIRATION- ROUTER OSPF mode to apply prefix lists to
incoming or outgoing OSPF routes
Command Syntax Command Mode Usage
distribute-list prefix-list-name in [interface] CONFIG-ROUTER-
OSPF
distribute-list prefix-list-name out
[connected | isis | rip | static]
CONFIG-ROUTER-
OSPF
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).
Apply a configured prefix list to
incoming OSPF routes.
Assign a configured prefix list to
outgoing OSPF routes.
552 Open Shortest Path First