Reference Guide

684 | Open Shortest Path First (OSPFv2 and OSPFv3)
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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.
For configuration information on prefix lists, refer to
IP Access Control Lists, Prefix Lists, and Route-maps
chapter in the
FTOS Configuration Guide.
Use the following commands in CONFIGURATION-ROUTER OSPF mode to apply prefix lists to
incoming or outgoing OSPF routes
Redistribute routes
You can add routes from other routing instances or protocols to the OSPF process. With the redistribute
command syntax, you can include RIP, static, or directly connected routes in 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
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).
Command Syntax Command Mode Usage
distribute-list prefix-list-name in [interface] CONFIG-ROUTER-OSPF-id Apply a configured prefix list to
incoming OSPF routes.
distribute-list prefix-list-name out
[connected | isis | rip | static]
CONFIG-ROUTER-OSPF-id Assign a configured prefix list to
outgoing OSPF routes.
Note: Do not route iBGP routes to OSPF unless there are route-maps associated with the OSPF
redistribution.