Lab 17. OSPF - Conditional Default Route

Conditional default route berfungsi agar R2 mengadvertise default route ke R1 jika jalur kearah ISP aktif. Tapi jika jalurnya terputus maka R2 tidak akan mengirimkan default route ke R1. Pertama hapus dulu settingan default route di lab sebelumnya

R1(config)#router ospf 1
R1(config-router)#no default-information originate always

Konfigurasi Default Route, jangan lupa hapus settingan di lab sebelumnya

R2(config)#router ospf 2
R2(config-router)#no network 23.23.23.0 0.0.0.255 area 0
R2(config)#ip route 0.0.0.0 0.0.0.0 23.23.23.3

R3(config)#router ospf 2
R3(config-router)#no network 23.23.23.0 0.0.0.255 area 0
R3(config)#ip route 0.0.0.0 0.0.0.0 23.23.23.2

Konfigurasikan route-map sebagai aturan untuk conditional default route

R2(config)#access-list 1 permit 23.23.23.0 0.0.0.255
R2(config)#route-map OSPF_defroute permit 10
R2(config-route-map)#match ip address 1
R2(config)#router ospf 2
R2(config-router)#default-information originate route-map OSPF_defroute

pastikan R1 mendapatkan default route

IDN-R1(config)#do sh ip route
Gateway of last resort is 12.12.12.2 to network 0.0.0.0
O*E2 0.0.0.0/0 [110/1] via 12.12.12.2, 00:05:44, Ethernet0/0
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/11] via 12.12.12.2, 02:12:13, Ethernet0/0
10.0.0.0/32 is subnetted, 3 subnets
C 10.10.10.1 is directly connected, Loopback1
C 10.10.10.2 is directly connected, Loopback2
C 10.10.10.3 is directly connected, Loopback3
12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 12.12.12.0/24 is directly connected, Ethernet0/0
L 12.12.12.1/32 is directly connected, Ethernet0/0

kita coba matikan interface e0/1 pada R2 yang menuju ke R3 (ISP)

R2(config)#int e0/1
R2(config-if)#shutdown

cek routing table R1 dan pastikan default route sudah hilang

R1(config)#do sh ip route
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/11] via 12.12.12.2, 02:05:52, Ethernet0/0
10.0.0.0/32 is subnetted, 3 subnets
C 10.10.10.1 is directly connected, Loopback1
C 10.10.10.2 is directly connected, Loopback2
C 10.10.10.3 is directly connected, Loopback3
12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 12.12.12.0/24 is directly connected, Ethernet0/0
L 12.12.12.1/32 is directly connected, Ethernet0/0

untuk mengeceknya lagi silahkan coba hidupakan kembali int e1/0 di R2 dan cek kembali routing table R1, jika konfigurasi sudah benar default route akakn muncul kembali di R1.

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