No shu
Ip os authentication
Ip os authentication-key cisco
Router os 110
Net 12.1.1.1 0.255.255.255 a 0 Net 23.2.2.2 0.255.255.255 a 0 Net 2.2.2.2 0.0.0.255 a 0 Area 0 authentication
R3：
Int l0
Ip add 3.3.3.3 255.255.255.0 Int s1/3
Ip add 23.2.2.3 255.255.255.0 No shu
Ip os authentication
Ip os authentication-key cisco
Router os 110
Net 3.3.3.3 0.0.0.255 a 0