here is a quick and dirty config to log failed and successful attempts on your router…
configuration terminal
enable secret cisco
username cisco secret password
line vty 0 4
login local
exit
logging 192.168.10.51
logging trap notification
login on-success log
loging on-failure log
logging block-for 120 attempts 2 within 60 !—-router will create an acl to block a failed attempt for 120 sec if there were 2 failed attempt within a 60 second time span.
login delay 5 !—time interval that can be done between failed attempts
logging source-interface fastEthernet0/0
Running-Config 