After posting about Fail2ban yester day I remembered that there is one more cool tool. The tool is Sshguard and is similar to Fail2ban. However, Sshguard is implemented in C and not a scripting language like Fail2ban (python). Sshguard also increases the ban time exponentially ... and that is nice.
I have not tested Sshguard yet but one of my friends highly recommends it.