What Knowledge Is Needed

Simple! to break something you must know how it was built. that is to say you must be good enough to build something like that. you must be able to think beyond the base of the program in question.

Its good to go the good way, do ethical hacking instead of criminal hacking that will save your life!

i do agree with skima, I hack once in a while but not network, but libraries (AJAX, Flex, etc) and modify it for my own use.

@poster: what are u really trying to become an hacker in?

A friend once told me that if u ask how to become and hacker, then you probably do not have the potential to become one, please don't ask me if it makes sense or not

Start with this link
http://www.catb.org/~esr/faqs/hacker-howto.html

What is ethical hacking? How can someone hack into libraries to modify its contents for his own good use? I'm not intrested in criminal hacking. I've sworn an oath when learning networking not to do criminal hacking with my knowledge and my personal decision is not to become a criminal hacker. But I've been noticing some hands on my e-mail and when I know who it is, i want to take revenge. If you've learnt networking, you will know that revenge is the most dangerous security treat. I'm not trying to become a criminal hacker!!!