R2#sh run | b Lo
interface Loopback0
 ip address 223.254.254.254 255.255.255.255
 ip pim sparse-dense-mode
!
interface Loopback1
 ip address 2.2.2.2 255.255.255.0
 ip ospf network point-to-point
!
interface Tunnel0
 ip address 24.24.24.2 255.255.255.0
 ip pim sparse-dense-mode
 keepalive 10 3
 tunnel source Loopback1
 tunnel destination 4.4.4.4
!
router ospf 1
 router-id 2.2.2.2
 log-adjacency-changes
 network 2.2.2.2 0.0.0.0 area 51
 network 180.40.7.2 0.0.0.0 area 51
 network 0.0.0.0 255.255.255.255 area 0
!


R3#sh run | b router
router ospf 1
 router-id 3.3.3.3
 log-adjacency-changes
 network 180.40.7.3 0.0.0.0 area 51
 network 180.40.7.129 0.0.0.0 area 51
 network 0.0.0.0 255.255.255.255 area 0
!


R4#sh run | b Lo
interface Loopback0
 ip address 4.4.4.4 255.255.255.0
!
interface Tunnel0
 ip address 24.24.24.4 255.255.255.0
 ip pim sparse-dense-mode
 keepalive 10 3
 tunnel source Loopback0
 tunnel destination 2.2.2.2
!
router ospf 1
 log-adjacency-changes
 network 4.4.4.4 0.0.0.0 area 51
 network 180.40.7.130 0.0.0.0 area 51
 network 0.0.0.0 255.255.255.255 area 0
!