denyhosts bans your repeated ssh brute force offenders and keeps your logfiles smaller.
install denyhosts if it is not already installed.
sudo apt-get -y install denyhosts
edit /etc/hosts.allow and add your allowed ip addresses or host names to whitelist, preventing you from locking yourself out.
sudo nano /etc/hosts.allow
add the following exceptions to the file, matching your hosts:
sshd: 18.104.22.168 sshd: 22.214.171.124
restart denyhosts to commit the changes immediately.
sudo /etc/init.d/denyhosts restart
for fine grain control concerning ban times and alerts, optionally edit /etc/denyhosts.conf and adjust to suit your level of tolerance.
sudo nano /etc/denyhosts.conf
done. denyhosts is installed and will run at boot time. most brute force ssh attempts should still be logged, but restrictions are now enforced to blacklist offenders and bots.