Proof Of Concepts : 2 default route, 2 ip adress, make it redundant??

seperti yang ditulis dari judul, gw hari ini lagi iseng ngelab untuk ngecek apakah apabila kita masukkan 2 default route ex : ip route 0.0.0.0 0.0.0.0 untuk 2 ip dalam satu interface (masukkan command secondary pada ip kedua) nah, apabila ip route satu dihapus, apakah dia akan masuk ke ip route yang lain
???

lets see

here's the configuration :
untuk R4 (gw cut yang nggak penting):
R4#sh ru
00:09:26: %SYS-5-CONFIG_I: Configured from console by consolen
Building configuration...

Current configuration:
!
version 12.1

!
hostname R4
!
!
memory-size iomem 15
ip subnet-zero
!
!
interface Loopback0
ip address 192.168.5.1 255.255.255.255
!
interface Loopback1
no ip address
!
interface FastEthernet0
ip address 192.168.4.2 255.255.255.252 secondary
ip address 192.168.3.2 255.255.255.252
speed auto
!
router eigrp 1
network 192.168.3.0 0.0.0.3
network 192.168.4.0 0.0.0.3
network 192.168.5.0 0.0.0.3
!
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.3.1
ip route 0.0.0.0 0.0.0.0 192.168.4.1 254
no ip http server
!
!
end
R4#

note :perhatikan bahwa gw masukin eigrp disitu untuk memasukkan loopback ke routing loop.

untuk R3 :

R3#show run
Building configuration...

Current configuration : 782 bytes
!
version 12.3
!
hostname R3
!
!
interface FastEthernet0/0
ip address 192.168.2.1 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.4.1 255.255.255.252 secondary
ip address 192.168.3.1 255.255.255.252
duplex auto
speed auto
!
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.3.2
ip route 0.0.0.0 0.0.0.0 192.168.2.2
ip route 0.0.0.0 0.0.0.0 192.168.4.2 254
ip http server
no ip http secure-server
!
!
line con 0
line aux 0
line vty 0 4

end

R3#

dan terakhir untuk R2 :

r2#show run
Building configuration...

*Mar 1 00:04:18.295: %SYS-5-CONFIG_I: Configured from console by console
Current configuration : 654 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname r2
!
boot-start-marker
boot-end-marker
!
!
memory-size iomem 10
no aaa new-model
ip subnet-zero
!
!
!
ip audit notify log
ip audit po max-events 100
no ftp-server write-enable
!
!
!
!
!
!
!
interface FastEthernet0/0
ip address 192.168.1.2 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.2.2 255.255.255.252
duplex auto
speed auto
!
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.2.1
ip http server
no ip http secure-server
!
!
!
!
line con 0
line aux 0
line vty 0 4
!
!
!
end

r2#

note : gw pentingin routing 192.168.3.0 ke default route, kita cek apakah bisa pindah ke 192.168.4.0 di routing table R3

screenshot :




nah timbul permasalahan. yaitu gimana cara ngakalin costnya, supaya setelah .3 down bisa pindah ke .4 tanpaaaa .2 yang menjadi kandidat route yang bakal ngakibatin semua mati

gw coba dengan ngubah ip 192.168.3.2 menjadi ip ngaco 1.1.1.1 255.255.255.255, jadi tentu saja routing ke sini semua putus dong??? bener nggak?

gimana caranya??

<10>

ternyata gampang, masukin aja semuanya lupakan cost (hehe):
jadi gini di R3 :
Gateway of last resort is 192.168.3.2 to network 0.0.0.0

192.168.4.0/30 is subnetted, 1 subnets
C 192.168.4.0 is directly connected, FastEthernet0/1
192.168.2.0/30 is subnetted, 1 subnets
C 192.168.2.0 is directly connected, FastEthernet0/0
192.168.3.0/30 is subnetted, 1 subnets
C 192.168.3.0 is directly connected, FastEthernet0/1
S* 0.0.0.0/0 [1/0] via 192.168.3.2
[1/0] via 192.168.2.2
[1/0] via 192.168.4.2

ketika di down host masih bisa kok ngeping ke 192.168.5.1, bukti bahwa dia lewat .4.2

helps?