Protecting your server from kiddies
Running Linux is great, most the viruses and hacks out there won't work against you as they are largely designed for Windows.
This though presents a false sense of security. And with always-on bot-nets it won't be long until somebody comes past your address with a port scanner and find you're running a FTP or SSH daemon.
I've been noticing an increasing number of hackers just plodding through dictionary attacks against my server. Hitting it time after time to see if they can brute force their way in.
A good policy on usernames and passwords will prevent them from ever succeeding, but why give them the benefit?
There is a great tool for Linux called Fail2Ban. What this does is check your security logs for signs of a brute force attack (e.g. multiple failures) and blocks any communication from that IP address for a period of time.
In a day it's already blocked 8 such attacks. Although these I would hazard a guess are done by bored teenagers as activity during the week is next to nothing - it's only at the weekend they seem to crop up.