san1#show run
!
interface Loopback0
 ip address 192.168.31.11 255.255.255.255
!
interface FastEthernet0/0
 ip address 192.168.1.1 255.255.255.0
 ip ospf message-digest-key 1 md5 cisco
 ip ospf hello-interval 5
 no sh
!
router ospf 1
 area 0 authentication message-digest
 network 192.168.1.0 0.0.0.255 area 0
!

san2#show run
!
interface Loopback0
 ip address 192.168.31.22 255.255.255.255
!
interface FastEthernet0/0
 ip address 192.168.1.2 255.255.255.0
 ip ospf message-digest-key 1 md5 cisco
 ip ospf hello-interval 5
 no sh
!
router ospf 1
 area 0 authentication message-digest
 network 192.168.1.0 0.0.0.255 area 0
!

san3#show run
!
interface Loopback0
 ip address 192.168.31.33 255.255.255.255
!
interface FastEthernet0/0
 ip address 192.168.1.3 255.255.255.0
 ip ospf message-digest-key 1 md5 cisco
 ip ospf hello-interval 5
 no sh
!
router ospf 1
 area 0 authentication message-digest
 network 192.168.1.0 0.0.0.255 area 0
!

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
show ip ospf nei 
show ip ospf nei de
show ip ospf int fa0/0
debug ip ospf events