Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring Routing Information (Rev. 03)
Controlling and Modifying Routing Information
© 2008 Foundry Networks, Inc.
Page 24 of 48
Table 11: Route Filtering Commands
Command
Description
ip prefix-list
Sets a prefix list to filter the routing information.
show ip prefix-list
Displays summary, detailed or specific information on IP prefix
lists, depending on command arguments.
clear ip prefix-list
Removes the specified entries from the prefix-list table.
route-map
Defines the route map and opens the Route-map Configuration
mode.
Configuring a Prefix List
The
ip prefix-list
command, in Global Configuration mode, sets a prefix list to filter the routing
information. The
no
form of this command removes the prefix list.
IPv4 prefix lists are used to define specific prefixes or a range of prefixes that must be matched
before a permit or deny statement can be applied. Two optional keywords can be used to designate
a range of prefix lengths to be matched.
An empty prefix list permits all prefixes. A prefix that does not match any entries of a prefix list is
denied.
The optional keywords
ge
and
le
that specify range limits on the prefix length can be used for
matching prefixes that are more specific than the exact prefix length. The user can use both
keywords (expressed as
ge
<
ge-value
> and
le
<l
e-value
>) in the same command. Their order is
immaterial.
The values following the
ge
and
le
keywords must comply with the following rules:
•
The g
e-value
may not exceed l
e-value
.
•
If only the
ge
attribute is specified, the range is assumed to be from
ge-value
to 32.
•
If only the
le
attribute is specified, the range is assumed to be from the exact prefix length to
le-value
.
•
If neither
ge
<
ge-value
> nor
le
<
le-value
> is specified, the matching criteria require an exact
match of the prefix length.
•
A specified
ge-value
and/or
le-value
must satisfy the following condition:
Exact prefix-length < ge-value <= le-value <= 32
Command Syntax
device-name
(config)#
ip prefix-list NAME
[
seq
<
sequence-number
>]
{
permit
|
deny
}
{
A.B.C.D/M
|
any
}
[
le
<
le-value
>]
[
ge
<
ge-value
>]
device-name
(config)#
ip prefix-list
{
NAME description .DESCRIPTION
|
sequence-number
}
device-name
(config)#
no ip prefix-list NAME
[[
seq
<
sequence-number
>]
{
permit
|
deny
}
{
A.B.C.D/M
|
any
}
[
le
<
le-value
>]
[
ge
<
ge-value
>]]
device-name
(config)#
no ip prefix-list
{
NAME description
[
.DESCRIPTION
]
|
sequence-number
}