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Defining filters
Configuration prerequisites
Before you configure this task, you must determine IP-prefix list name, matching address range, and
extcommunity list sequence number.
Defining an IP prefix list
Defining 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.
To define an IPv4 prefix list:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Define an IPv4
prefix list.
ip ip-prefix
ip-prefix-name
[
index
index-number
]
{
deny
|
permit
}
ip-address mask-length
[
greater-equal
min-mask-length
] [
less-equal
max-mask-length
]
Not defined by default.
If all the items are set to the
deny
mode, no routes can pass the IPv4 prefix list. You must 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
Defining an IPv6 prefix list
Identified by name, each IPv6 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 IPv6 prefix list is passed,
and the routing information will not go to the next item.
To define an IPv6 prefix list:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
