R1
                                    | 
                                       RIP
                                    |
                                   R2
                                    |
                                       OSPF
                                    |
                                   R3
R1#show running-config
!
hostname R1
!
interface Loopback0
 ip address 10.0.0.1 255.0.0.0
!
interface Serial1/1
 ip address 20.0.0.1 255.0.0.0
 serial restart-delay 0
!
router rip
 network 10.0.0.0
 network 20.0.0.0
 default-information originate
!
ip route 0.0.0.0 0.0.0.0 20.0.0.2

R2#show running-config
!
hostname R2
!
interface Serial1/0
 ip address 20.0.0.2 255.0.0.0
 serial restart-delay 0
!
interface Serial1/1
 ip address 30.0.0.1 255.0.0.0
 serial restart-delay 0
!
router ospf 1
 log-adjacency-changes
 network 30.0.0.0 0.0.0.255 area 0
!
router rip
 network 20.0.0.0

R3#show running-config
!
hostname R3
!
interface Loopback0
 ip address 40.0.0.1 255.0.0.0
!
interface Serial1/0
 ip address 30.0.0.2 255.0.0.0
 serial restart-delay 0
!
router ospf 1
 log-adjacency-changes
 network 30.0.0.0 0.0.0.255 area 0
 network 40.0.0.0 0.0.0.255 area 0
 default-information originate
!
ip route 0.0.0.0 0.0.0.0 30.0.0.1

 

R1#show ip rou
C    20.0.0.0/8 is directly connected, Serial1/1
C    10.0.0.0/8 is directly connected, Loopback0
S*   0.0.0.0/0 [1/0] via 20.0.0.2

R2#show ip rou
C    20.0.0.0/8 is directly connected, Serial1/0
     40.0.0.0/32 is subnetted, 1 subnets
O       40.0.0.1 [110/65] via 30.0.0.2, 00:00:16, Serial1/1
R    10.0.0.0/8 [120/1] via 20.0.0.1, 00:00:16, Serial1/0
C    30.0.0.0/8 is directly connected, Serial1/1
O*E2 0.0.0.0/0 [110/1] via 30.0.0.2, 00:00:16, Serial1/1

R3#show ip rou
C    40.0.0.0/8 is directly connected, Loopback0
C    30.0.0.0/8 is directly connected, Serial1/0
S*   0.0.0.0/0 [1/0] via 30.0.0.1