Because fail2ban is not available from CentOS, we should start by downloading the EPEL repository:

rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

Follow up by installing fail2ban:

yum install fail2ban

The default fail2ban configuration file is location at /etc/fail2ban/jail.conf. The configuration work should not be done in that file, however, and we should instead make a local copy of it.

cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local

After the file is copied, you can make all of your changes within the new jail.local file. Many of possible services that may need protection are in the file already. Each is located in its own section, configured and turned off.

Set up a few rules on a plesk server with CentOS

SSH

[ssh-iptables]

enabled  = true
filter   = sshd
action   = iptables[name=SSH, port=10222, protocol=tcp]
           sendmail-whois[name=SSH, dest=root, sender=admin@domain.com, sendername="Fail2Ban"]
logpath  = /var/log/secure
maxretry = 5

* Notice ssh is set up on port 10222

ProFTP

[proftpd-iptables]

enabled  = true
filter   = proftpd
action   = iptables[name=ProFTPD, port=ftp, protocol=tcp]
           sendmail-whois[name=ProFTPD, dest=admin@domain.com]
logpath  = /var/log/secure
maxretry = 5

* Notice the log location. This is for a Plesk server as proftpd logs to /var/log/secure
Restart fail2ban

# service fail2ban restart

Postfix

# This jail forces the backend to "polling".
[sasl-iptables]

enabled  = true
filter   = postfix-sasl
backend  = polling
action   = iptables[name=sasl, port=smtp, protocol=tcp]
           sendmail-whois[name=sasl, dest=admin@domain.com]
logpath  = /usr/local/psa/var/log/maillog

Postfix

[postfix-tcpwrapper]

enabled  = true
filter   = postfix
action   = hostsdeny[file=/etc/fail2ban/hosts.deny]
           sendmail[name=Postfix, dest=admin@domain.com]
logpath  = /usr/local/psa/var/log/maillog
bantime  = 300

Apache Auth

[apache-tcpwrapper]

enabled  = true
filter   = apache-auth
action   = iptables[name=apache, port=apache, protocol=tcp]
           sendmail-whois[name=apache, dest=admin@domain.com]
logpath  = /var/log/httpd/error_log
#           /home/www/myhomepage/error.log
maxretry = 6