ip prefix-list

Configures a RIP routing prefix list that can permit or deny specific routes. The prefix list can be applied globally or to individual interfaces, where they may apply to incoming (learned) our outgoing (advertised) routes.
Syntax
ip prefix-list name [ seq number ] { permit | deny } { source-ip-address / L }
ip prefix-list name description string
no ip prefix-list name [ seq number ] { permit | deny } { source-ip-address / L }
no ip prefix-list name description string
Command Default

By default, routes that do not match a prefix list are learned or advertised. To prevent a route from being learned or advertised, you must configure and apply a prefix list to deny the route.

Parameters
name
Identifies the prefix list.
description string
Provides information describing the named prefix list in an ASCII string.
seq number
Specifies an optional sequence number for the named prefix list.
permit
Indicates that designated routes will be allowed; that is, either learned or advertised, depending on how the prefix list is applied.
deny
Indicates that designated routes will be denied; that is, will not be learned or will not be advertised, depending on how the prefix list is applied.
source-ip-address / L
Designates a specific route, based on its IP address prefix and mask length.
[ ge value ] [ le value ]
The keyword le indicates the maximum prefix length that can be matched. The keyword ge indicates minimum prefix length that can match. Possible values for ge (greater than or equal to) and le (less than or equal to) are 1 through 32. The ge and le values can be used separately or together.
Modes

Global configuration mode

Usage Guidelines

The no form of the command disables the prefix list.

A route is defined by the destination’s IP address and network mask. Because the default action is permit, all other routes (routes not explicitly permitted or denied by the filters) can be learned or advertised.

Prefix lists can be applied to RIP globally using the separate prefix-list command or at the interface level using the separate ip rip prefix-list command.

Examples

The following example creates four prefix lists. Three of the prefix lists permit a route for a different network. The last prefix list denies a route for one network. The routes are defined but not applied in the example. 

device# configure terminal
device(config)# ip prefix-list list1 permit 10.53.4.1 255.255.255.0
device(config)# ip prefix-list list2 permit 10.53.5.1 255.255.255.0
device(config)# ip prefix-list list3 permit 10.53.6.1 255.255.255.0
device(config)# ip prefix-list list4 deny 10.53.7.1 255.255.255.0
Parent topic: Commands I