R1 Router
enable
conf terminal
hostname R1
int fa0/0
description link R1 to LAN 1
ip address 172.16.3.1 255.255.255.0
no shutdown 
exit
int serial2/0
description link R1 to R2
ip address 172.16.2.1 255.255.255.0
no shutdown 
exit


R2 Router
enable
conf terminal
hostname R2
int fa0/0
description link R2 to LAN 2
ip address 172.16.1.1 255.255.255.0
no shutdown 
exit
int serial2/0
description link R2 to R1
ip address 172.16.2.2 255.255.255.0
no shutdown 
exit
int serial3/0
description link R2 to R3
ip address 192.168.1.2 255.255.255.0
no shutdown 
exit

R3 Router
enable
conf terminal
hostname R3
int fa0/0
description link R1 to LAN 1
ip address 192.168.2.1 255.255.255.0
no shutdown 
exit
int serial2/0
description link R1 to R2
ip address 192.168.1.1 255.255.255.0
no shutdown 
exit

Static Routing  R1
enable
conf terminal
ip route 172.16.1.0 255.255.255.0 172.16.2.2
ip route 192.168.1.0 255.255.255.0 172.16.2.2
ip route 192.168.2.0 255.255.255.0 172.16.2.2

Static Routing  R3
enable
conf terminal
ip route 172.16.1.0 255.255.255.0 192.168.1.2
ip route 172.16.2.0 255.255.255.0 192.168.1.2
ip route 172.16.3.0 255.255.255.0 192.168.1.2

Static Routing  R2
enable
conf terminal
ip route 172.16.3.0 255.255.255.0 172.16.2.1
ip route 192.168.2.0 255.255.255.0 192.168.1.1

Default routing R1
enable
conf terminal
ip route 0.0.0.0 0.0.0.0 172.16.2.2

Default routing R2
enable
conf terminal
ip route 0.0.0.0 0.0.0.0 172.16.2.1
ip route 0.0.0.0 0.0.0.0 192.168.1.1


Default routing R3
enable
conf terminal
ip route 0.0.0.0 0.0.0.0 192.168.1.2

R1 to R3
enable
conf terminal
int serial3/0
description link R1 to R3
ip address 10.10.10.1 255.255.255.0
no shutdown 
exit


R3 to R1
enable
conf terminal
int serial3/0
description link R3 to R1
ip address 10.10.10.2 255.255.255.0
no shutdown 
exit

R1
enable 
conf terminal
ip route 0.0.0.0 0.0.0.0 10.10.10.2 5

R3
enable 
conf terminal
ip route 0.0.0.0 0.0.0.0 10.10.10.1 5

RIP R1
enable 
conf terminal
router RIP
network 172.16.3.0
network 172.16.2.0
network 10.10.10.0

RIP R2
enable 
conf terminal
router RIP
network 172.16.1.0
network 172.16.2.0
network 192.168.1.0

RIP R2
enable 
conf terminal
router RIP
network 192.168.1.0
network 192.168.2.0
network 10.10.10.0