对接收和发布的路由进行过滤
如下图所示，网络内R1、R2、R3运行OSPF协议，R4有四个网段路由，要求OSPF只能访问10.1.1.0/24、10.1.2.0/24、10.1.3.0/24三个网段，R1只能访问10.1.1.0/24网段；
配置接口IP地址：
[r1]int g0/0/0
[r1-GigabitEthernet0/0/0]ip address 12.1.1.1 24
配置OSPF协议：
[r1]ospf 100 router-id 1.1.1.1
[r1-ospf-100]area 0
[r1-ospf-100-area-0.0.0.0]network 13.1.1.0 0.0.0.255
[r2]ospf 100 router-id 2.2.2.2
[r2-ospf-100]area 0
[r2-ospf-100-area-0.0.0.0]network 23.1.1.0 0.0.0.255
[r3]ospf 100 router-id 3.3.3.3
[r3-ospf-100]area 0
[r3-ospf-100-area-0.0.0.0]network 13.1.1.0 0.0.0.255
[r3-ospf-100-area-0.0.0.0]network 23.1.1.0 0.0.0.255
[r3-ospf-100-area-0.0.0.0]network 34.1.1.0 0.0.0.255
[r4]ospf 100 router-id 4.4.4.4
[r4-ospf-100]area 0
[r4-ospf-100-area-0.0.0.0]network 34.1.1.0 0.0.0.255
配置静态路由并引入OSPF协议中：
[r4]ip route-static 10.1.1.1 24 NULL 0
[r4]ip route-static 10.1.2.1 24 NULL 0
[r4]ip route-static 10.1.3.1 24 NULL 0
[r4]ip route-static 10.1.4.1 24 NULL 0
[r4]ospf 100
[r4-ospf-100]import-route static
查看原始路由信息：
[r1]display ip routing-table protocol ospf
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Public routing table : OSPF
Destinations : 6 Routes : 6
OSPF routing table status : <Active>
Destinations : 6 Routes : 6
Destination/Mask Proto Pre Cost Flags NextHop Interface
10.1.1.0/24 O_ASE 150 1 D 13.1.1.2 GigabitEthernet0/0/0
10.1.2.0/24 O_ASE 150 1 D 13.1.1.2 GigabitEthernet0/0/0
10.1.3.0/24 O_ASE 150 1 D 13.1.1.2 GigabitEthernet0/0/0
10.1.4.0/24 O_ASE 150 1 D 13.1.1.2 GigabitEthernet0/0/0
23.1.1.0/24 OSPF 10 2 D 13.1.1.2 GigabitEthernet0/0/0
34.1.1.0/24 OSPF 10 2 D 13.1.1.2 GigabitEthernet0/0/0
OSPF routing table status : <Inactive>
Destinations : 0 Routes : 0
配置前缀列表：
[r4]ip ip-prefix aaa index 5 permit 10.1.1.1 24
[r4]ip ip-prefix aaa index 10 permit 10.1.2.1 24
[r4]ip ip-prefix aaa index 15 permit 10.1.3.1 24
[r4]ospf 100
[r4-ospf-100]filter-policy ip-prefix aaa export static
[r1]ip ip-prefix aaa index 5 permit 10.1.1.1 24
[r1]ospf 100
[r1-ospf-100]filter-policy ip-prefix aaa import
查看R3配置后的路由信息：
[r3]display ip routing-table protocol ospf
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Public routing table : OSPF
Destinations : 3 Routes : 3
OSPF routing table status : <Active>
Destinations : 3 Routes : 3
Destination/Mask Proto Pre Cost Flags NextHop Interface
10.1.1.0/24 O_ASE 150 1 D 34.1.1.2 GigabitEthernet0/0/2
10.1.2.0/24 O_ASE 150 1 D 34.1.1.2 GigabitEthernet0/0/2
10.1.3.0/24 O_ASE 150 1 D 34.1.1.2 GigabitEthernet0/0/2
OSPF routing table status : <Inactive>
Destinations : 0 Routes : 0
查看R1配置后的路由信息：
[r1]display ip routing-table protocol ospf
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Public routing table : OSPF
Destinations : 1 Routes : 1
OSPF routing table status : <Active>
Destinations : 1 Routes : 1
Destination/Mask Proto Pre Cost Flags NextHop Interface
10.1.1.0/24 O_ASE 150 1 D 13.1.1.2 GigabitEthernet0/0/0
OSPF routing table status : <Inactive>
Destinations : 0 Routes : 0