@dee

Fail2Ban:
ban hosts that cause multiple authentication errors

Fail2Ban scans log files like /var/log/auth.log and bans IP addresses conducting too many failed login attempts.

It does this by updating system firewall rules to reject new connections from those IP addresses, for a configurable amount of time.

Fail2Ban comes out-of-the-box ready to read many standard log files, such as those for sshd and Apache,
and is easily configured to read any log file of your choosing, for any error you wish.

Though Fail2Ban is able to reduce the rate of incorrect authentication attempts,
it cannot eliminate the risk presented by weak authentication.

Set up services to use only two factor, or public/private authentication mechanisms if you really want to protect services.