New computer users normally are intrigued by the the term known as "Hacking". Let me clarify what is hacking and what is the difference between Ethical and non-ethical Hacking according to my experience.

What is Hacking?

Answer.com says.. "Hacking is .. Use of a computer system without a specific, constructive purpose, or without proper authorization."

Well, I disagree to that.. Hacking is nothing but a clever or quick fix to a computer program problem, or to what may be perceived to be a clumsy or inelegant (but usually relatively quick) solution to a problem.

Infact.. there is a community, a shared culture, of expert programmers and networking wizards that traces its history back through decades to the first time-sharing minicomputers and the earliest ARPAnet experiments. The members of this culture originated the term ‘hacker’. Hackers built the Internet. Hackers made the Unix operating system what it is today. Hackers run Usenet. Hackers make the World Wide Web work. If you are part of this culture, if you have contributed to it and other people in it know who you are and call you a hacker, you're a hacker.

What is the difference between Hacking and Ethical Hacking?

To be frank there is no term as Ethical hacking :). Experts use two terms to distinguish between a good hacker and a bad hacker..
"Hackers: they build things, Crackers: they destroy things"

So, How do I learn hacking?

Now this is an art which needs patience and knowledge, you cannot download a "Hack yahoo passwords" tool , enter a yahoo id and get its password. Its lame.

Hackers solve problems and build things, and they believe in freedom and voluntary mutual help. But if you think of cultivating hacker attitudes as just a way to gain acceptance in the culture, you'll miss the point. Becoming the kind of person who believes these things is important for you — for helping you learn and keeping you motivated. As with all creative arts, the most effective way to become a master is to imitate the mind-set of masters — not just intellectually but emotionally as well.

Lets start from the basics

The following tutorial is very basic and can be used a starting point in learning the art of network Hacking. Prerequisites: Basic knowledge of OSI model.

As we know, most of the computer or device on the network runs over TCP/IP protocol which  works on 4 layers.

* Link layer
* Internet layer
* Transport layer
* Application layer

Consider the transport layer, which works on the basis on port numbers. So, when you type http://google.com in your browser you actually are connecting to a server on port number 80.

Now that server can serve you web pages provided that it is running a web server software which by default listens on port 80.

Before moving forward..

As this point of time, I will introduce 2 more terms used frequently in the world of Hacking.

* Vulnerability
Simple definition: A bug or loophole in software which allows it to be compromised locally or from the network.
* Exploit
Simple definition: The tool or program used to take advantage of that particular vulnerability.

For e.g Microsoft IIS server 5.0 had a vulnerability (Chunk encoding) which allows any body in the network (internet) to take over the whole machine using a simple program (exploit).
ref: http://www.securityfocus.com/bid/4485

In the next part of this article.. we will learn how to explore whether a machine is running a web server program (on port 80) and then how to use an exploit to take over a vulnerable web server.

PS: Feel free to comment on this article.