Fail2ban is fundamentally a wrong answer to the problem. If you're taking the time to install such things, you should instead either be turning off password authentication (relying only on keys) or shorewall (to default deny ssh access except to authorized subnets) or both.
Waiting for multiple authentication failures to mark a host/net as "bad" is fundamentally a bad idea. Stop using passwords.
Waiting for multiple authentication failures to mark a host/net as "bad" is fundamentally a bad idea. Stop using passwords.