enable
config t
interface GigabitEthernet 0/0
ip ospf message-digest-key 1 md5 testing
ip ospf authentication message-digest
enable
config t
interface GigabitEthernet 0/0
ip ospf message-digest-key 1 md5 testing
ip ospf authentication message-digest
enable
config t
interface GigabitEthernet 0/0
ip ospf message-digest-key 1 md5 testing
ip ospf authentication message-digest
exit
interface GigabitEthernet 0/1
ip ospf message-digest-key 1 md5 testing
ip ospf authentication message-digest
exit
interface GigabitEthernet 0/2
ip ospf message-digest-key 1 md5 testing
ip ospf authentication message-digest
enable
config t
interface GigabitEthernet 0/0
ip ospf message-digest-key 1 md5 testing
ip ospf authentication message-digest
If you run the command below it will show all ospf configuration on the specified interface
show ip ospf interface {interface} {interface #}
show ip ospf interface gigabitEthernet 0/0