It's a well known fact that chinese scan ports, brute force and exploit like crazy. It will help alot if you just drop whole China in your firewall. It's not hard to do - just dig up chinese ip networks and block them.
And the first thing you should do is to install a simple and rather nice tool: [Hidden Content]
Or if you have a little more admin experience then go for: [Hidden Content]
There are also other good methods to screw scanners e.g. port knocking or just use key-based auth as suggested above.
