Day 3 - OSPF - Filtering - AD

Pada routing OSPF, selain menggunakan distribute-list, cara filtering lainnya adalah dengan menggunakan AD.

Lab kali ini kita akan membahas bagaimana cara melakukan filtering menggunakan AD pada OSPF.

Lab 13 - OSPF - Filtering - AD

Topologi yang digunakan adalah sbb :


Konfigurasi R1 :

interface Loopback0
 ip address 1.1.1.1 255.255.255.255
!
interface Loopback1
 ip address 100.100.100.1 255.255.255.255
!
interface Loopback2
 ip address 100.100.100.2 255.255.255.255
!
interface Loopback3
 ip address 100.100.100.3 255.255.255.255
!
interface Loopback4
 ip address 100.100.100.4 255.255.255.255
!
interface Serial0/0
 ip address 12.12.12.1 255.255.255.0
!

router ospf 1
 router-id 1.1.1.1
 log-adjacency-changes
 network 0.0.0.0 255.255.255.255 area 0

Konfigurasi R2 :

interface Loopback0
 ip address 2.2.2.2 255.255.255.255
!
interface FastEthernet0/0
 ip address 23.23.23.2 255.255.255.0
!
interface Serial0/0
 ip address 12.12.12.2 255.255.255.0
!

router ospf 1
 router-id 2.2.2.2
 log-adjacency-changes
 network 0.0.0.0 255.255.255.255 area 0

Konfigurasi R3 :

interface Loopback0
 ip address 3.3.3.3 255.255.255.255
!
interface FastEthernet0/0
 ip address 23.23.23.3 255.255.255.0
!

router ospf 1
 router-id 3.3.3.3
 log-adjacency-changes
 network 0.0.0.0 255.255.255.255 area 0

Kita cek routing table di R2 :

R2#sh ip route
Gateway of last resort is not set

     1.0.0.0/32 is subnetted, 1 subnets
O       1.1.1.1 [110/65] via 12.12.12.1, 00:01:18, Serial0/0
     2.0.0.0/32 is subnetted, 1 subnets
C       2.2.2.2 is directly connected, Loopback0
     100.0.0.0/32 is subnetted, 4 subnetsO       100.100.100.4 [110/65] via 12.12.12.1, 00:01:18, Serial0/0
O       100.100.100.1 [110/65] via 12.12.12.1, 00:01:18, Serial0/0
O       100.100.100.2 [110/65] via 12.12.12.1, 00:01:18, Serial0/0
O       100.100.100.3 [110/65] via 12.12.12.1, 00:01:18, Serial0/0
     3.0.0.0/32 is subnetted, 1 subnets
O       3.3.3.3 [110/11] via 23.23.23.3, 00:01:18, FastEthernet0/0
     23.0.0.0/24 is subnetted, 1 subnets
C       23.23.23.0 is directly connected, FastEthernet0/0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, Serial0/0

Terlihat bahwa untuk IP Loopback R1 sudah diterima oleh R2 via routing OSPF.
Sekarang kita coba lakukan filtering IP Loopback R1 100.100.100.2 di router R2.

R2(config)#access-list 1 permit host 100.100.100.2
R2(config)#router ospf 1
R2(config-router)#distance 255 0.0.0.0 255.255.255.255 1
 
Kita coba cek lagi routing table di R2 :

R2(config-router)#do sh ip route

Gateway of last resort is not set

     1.0.0.0/32 is subnetted, 1 subnets
O       1.1.1.1 [110/65] via 12.12.12.1, 00:00:19, Serial0/0
     2.0.0.0/32 is subnetted, 1 subnets
C       2.2.2.2 is directly connected, Loopback0
     100.0.0.0/32 is subnetted, 3 subnets
O       100.100.100.4 [110/65] via 12.12.12.1, 00:00:19, Serial0/0
O       100.100.100.1 [110/65] via 12.12.12.1, 00:00:19, Serial0/0
O       100.100.100.3 [110/65] via 12.12.12.1, 00:00:19, Serial0/0
     3.0.0.0/32 is subnetted, 1 subnets
O       3.3.3.3 [110/11] via 23.23.23.3, 00:00:19, FastEthernet0/0
     23.0.0.0/24 is subnetted, 1 subnets
C       23.23.23.0 is directly connected, FastEthernet0/0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, Serial0/0

Terlihat bahwa untuk routing IP Loopback 100.100.100.2 sudah hilang dari routing table R2.
Sehingga bisa kita simpulkan bahwa untuk filtering AD yang sudah kita buat sudah berhasil :)