I won’t go into much details but you’ll get the idea.
First off, every computer, at a given time, has a unique IP adress, that’s what identifies them on the internet. Even when you use a string of words (like www.hardwareforums.com ), what you’re really doing is asking the DNS (Domain Name Server) what is the IP that is associated with that name, and then it can find its way.
So when you enter an adress, it tries to find its way through your local network. If it can’t, it asks the gateway if it knows that adress or if it knows what gateway knows that adress. The gateway is a computer that is between you, and the rest of the world. Once it has reached its goal, the gateway will try to associate the IP with your MAC adress. The Mac adress is an adress that is burnt into your network card and it is truly unique. You won’t find two network cards with the same MAC adress. It’s impossible. Once it has made the association, it will send the signal to the network where your computer is.
That’s why we say the internet is a network of networks. Not every network has a direct access to every other networks, but there’s always a path that will lead you there.
Now you got a hub, a switch and a router.
If you have a hub, all it does is take the signal and send it to everyone it can.
If you have a switch, it will only send the signal to the right network card.
And if you have a router, that’s like a switch but only certain ports are opened so you have to transfer you signals through those ports if you wanna’ transmit/receive anything.
Of course, a switch is a lot better than a hub because:
- Not everyone will be able to intercept the signal
- It’s not a bandwidth hog like the hub which uses it all all the time.
So basically, you have access to all the signals that travel in your network. The thing is the signal won’t get to you if it’s not intended to you. Unless you have a program that gives you the ability to do that, then you’re a “hacker”.
You also have to understand that there is a difference between a hacker and a cracker and that there are 3 different kinds of hackers.
hackers:
White-hats: They usually are experts in security that work for big companies or network genius that do this from home. They sometimes try to infiltrate huge systems to find the flaws and then contact the company to inform them. There intentions are good but what would you say if someone entered your home and told you:“hey look you should fix that cause I can come in whenever I want” ???
Black-hats (Crackers): They infiltrate and damage or steal information from others for their own sake or money. Those are the people you gotta be aware of.
Grey-hats: Obviously, this is somewhere between those two.