Useful commands
set the console password
router(config)# line con 0
router(config-line)# password mysecret
set the vty passwords
router(config-line)# line vty 0 4
router(config-line)# password mysecret
router(config-line)# exit
set the enable password
router(config)# enable password mysecret
router(config)# service password-encryption
router(config)# ^Z