fail2ban scans log files and bans IP addresses that makes too many failures

fail2ban scans log files like /var/log/messages and bans IP addresses
that makes too many password failures. It updates firewall rules to
reject the IP address, can send e-mails, or set host.deny entries.
These rules can be defined by the user. Fail2Ban can read multiple log
files such as sshd or Apache web server ones.