configure fail2ban to startup on boot
chkconfig --add fail2ban # chkconfig fail2ban on
Informative sources
Protecting your server from attacks with fail2ban
- tips for setting up fail2ban for apache, dovecot, etc
Blocking brute force attacks to Dovecot on CentOS
- has clear regex example. wrongly suggests directly editing jail.conf
How To Protect SSH with fail2ban on CentOS 6
- very current, however, specific to protecting ssh, not covering dovecot
- somewhat outdated. documentation from dovecot site.
Secure a CentOS 6 Mail server with Fail2ban
- in theory this should be the most current and specific guide.