核心配置

R1

ip route-static 3.3.3.3 255.255.255.255 GigabitEthernet0/0/0 10.1.1.2

ip route-static 3.3.3.3 255.255.255.255 GigabitEthernet0/0/1 20.1.1.2

ip route-static 30.1.1.0 255.255.255.0 GigabitEthernet0/0/0 10.1.1.2

ip route-static 30.1.1.0 255.255.255.0 GigabitEthernet0/0/1 20.1.1.2

R2

ip route-static 1.1.1.1 255.255.255.255 GigabitEthernet0/0/0 10.1.1.1

ip route-static 1.1.1.1 255.255.255.255 GigabitEthernet0/0/1 20.1.1.1

ip route-static 3.3.3.3 255.255.255.255 GigabitEthernet0/0/2 30.1.1.3

R3

ip route-static 1.1.1.1 255.255.255.255 GigabitEthernet0/0/0 30.1.1.2

ip route-static 10.1.1.0 255.255.255.0 GigabitEthernet0/0/0 30.1.1.2

ip route-static 20.1.1.0 255.255.255.0 GigabitEthernet0/0/0 30.1.1.2

原理

R1

R3

R2