1-3
Task
Defining Filters
Defining an IP-prefix List
Creating a Route Policy
Defining if-match Clauses
Configuring a Route Policy
Defining apply Clauses
Defining Filters
Prerequisites
Before configuring this task, you need to decide on:
z
IP-prefix list name
z
Matching address range
Defining an IP-prefix List
Define an IPv4 prefix list
Identified by name, an IPv4 prefix list can comprise multiple items. Each item specifies a prefix range to
match and is identified by an index number.
An item with a smaller index number is matched first. If one item is matched, the IP prefix list is passed,
and the routing information will not go to the next item.
Follow these steps to define an IPv4 prefix list:
To do…
Use the command…
Remarks
Enter system view
system-view
—
Define an IPv4 prefix
list
ip ip-prefix
ip-prefix-name
[
index
index-number
] {
permit
|
deny
}
ip-address
mask-length
[
greater-equal
min-mask-length
]
[
less-equal
max-mask-length
]
Required
Not defined by default.
If all the items are set to the
deny
mode, no routes can pass the IPv4 prefix list. Therefore, you need to
define the
permit
0.0.0.0 0
less-equal
32 item following multiple
deny
items to allow other IPv4 routing
information to pass.
For example, the following configuration filters routes 10.1.0.0/16, 10.2.0.0/16 and 10.3.0.0/16, but
allows other routes to pass.
<Sysname> system-view
[Sysname] ip ip-prefix abc index 10 deny 10.1.0.0 16
[Sysname] ip ip-prefix abc index 20 deny 10.2.0.0 16
[Sysname] ip ip-prefix abc index 30 deny 10.3.0.0 16
[Sysname] ip ip-prefix abc index 40 permit 0.0.0.0 0 less-equal 32
