Basic Firewall tutorial.
The number ONE all time best hacking tool that absolutely can NOT be done without, is your mind; and learning to look at a problem from all angles and even after finding a solution to a problem trying to arrive at the same solution using different means to arrive at the same conclusion of solution.
The same tool (your mind) is also the best protection against hack attempts, this will always be the fight between minds and the strongest will win, atleast temporary since the struggle always will continue.
But it's always wise to use good tools aswell and that is what this basic tutorial is all about.
To save space have I attached the tutorial instead of post it in this forum.