Fail2ban для защиты SSH

Установка Fail2ban на Debian/Ubuntu:

apt-get install fail2ban

Установка Fail2ban на CentOS/Fedora/RHEL:

yum install fail2ban

nano /etc/fail2ban/jail.local

[DEFAULT]
## Постоянный IP-адрес.
## Если не переопределить ignoreip здесь,
## то стоит закомментировать этот параметр в jail.conf.
ignoreip = 57.66.158.131

[ssh]
## если в течении 1 часа:
findtime = 3600
## произведено 6 неудачных попыток логина:
maxretry = 6
## то банить IP на 24 часа:
bantime = 86400

service fail2ban restart

* Restarting authentication failure monitor fail2ban [ OK ]

tail /var/log/fail2ban.log

2014-07-17 17:31:36,990 fail2ban.jail : INFO Jail 'ssh' stopped
2014-07-17 17:31:36,991 fail2ban.server : INFO Exiting Fail2ban
2014-07-17 17:31:37,419 fail2ban.server : INFO Changed logging target to /var/log/fail2ban.log for Fail2ban v0.8.6
2014-07-17 17:31:37,420 fail2ban.jail : INFO Creating new jail 'ssh'
2014-07-17 17:31:37,423 fail2ban.jail : INFO Jail 'ssh' uses Gamin
2014-07-17 17:31:37,443 fail2ban.filter : INFO Added logfile = /var/log/auth.log
2014-07-17 17:31:37,443 fail2ban.filter : INFO Set maxRetry = 6
2014-07-17 17:31:37,445 fail2ban.filter : INFO Set findtime = 3600
2014-07-17 17:31:37,446 fail2ban.actions: INFO Set banTime = 86400
2014-07-17 17:31:37,492 fail2ban.jail : INFO Jail 'ssh' started

http://putty.org.ru/articles/fail2ban-ssh.html