Router(config)#router ospf 456
Router(config-router)#area 0 authentication message-digest
Enables authentication with MD5 password encryption
Router(config-router)#exit
Router(config)#int fa 0/0
Router(config-if)#ip ospf message-digest-key 1 md5 fred
1 is the key-id. This value must be the same as that of the neighboring router
md5 indicates that the MD5 hash algorithm will be used
fred is the key (password) and must be the same as that of the neighboring router
