Lab Requirements:
1. The router names are p4s1, p4s2 and p4s3.
2. Configure default routes on p4s1 and p4s3.
3. Configure a static route on p4s2.

Lab Process:
1. Configure p4s1
Router>enable
Router#configure terminal
Router(config)#hostname P4S1
P4S1(config)#interface s1/1
P4S1(config-if)#ip add 192.168.12.1 255.255.255.0
P4S1(config-if)#no shut
P4S1(config-if)#interface loopback 0
P4S1(config-if)#ip add 1.1.1.1 255.255.255.0

2. Configure p4s2
Router>enable
Router#configure terminal
Router(config)#host P4S2
P4S2(config)#interface s1/1
P4S2(config-if)#ip add 192.168.12.2 255.255.255.0
P4S2(config-if)#no shut
P4S2(config)#interface s1/2
P4S2(config-if)#ip add 192.168.23.2 255.255.255.0
P4S2(config-if)#no shut

3. Configure p4s3
Router>enable
Router#configure terminal
Router(config)#host P4S3
P4S3(config)#int s1/1
P4S3(config-if)#ip add 192.168.23.3 255.255.255.0
P4S3(config-if)#no shut
P4S3(config)#interface loopback 0
P4S3(config-if)#ip add 3.3.3.3 255.255.255.0

Configure default routes on p4s1 and p4s3 and a static route on p4s2.
P4S1
P4S1(config)#ip route 0.0.0.0 0.0.0.0 192.168.12.2

P4S3
P4S3(config)#ip route 0.0.0.0 0.0.0.0 192.168.23.2

P4S2
P4S2(config)#ip route 1.1.1.0 255.255.255.0 192.168.12.1
P4S2(config)#ip route 3.3.3.0 255.255.255.0 192.168.23.3

Authentication:
Use the extended ping command on the p4s1 or p4s3 to test connectivity.