iptables: Blocking attacking IP addresses

Excellent article on using iptables to block an attacking IP address.

http://www.cyberciti.biz/faq/linux-iptables-drop/

I needed to block a known russian SSH/SFTP hacker.

Code:   

iptables -A INPUT -s 91.205.189.27/255.255.255.255 -j DROP

   


Even better for automated blocking of attackers is denyhosts. DenyHosts is a script intended to be run by Linux system administrators to help thwart SSH server attacks (also known as dictionary based attacks and brute force attacks).

http://www.cyberciti.biz/faq/block-ssh-attacks-with-denyhosts/