Is your computer a zombie? We can help.

Imagine a wall 256′ by 256′ with a grid on it like a graph.  These squares are numbered 1 through 65,535 because the top right square is missing.  The numbering starts at the bottom left, works its way right, goes up a row and all the way to the left and continues right until it reaches the top.  Now imagine you’re good at golf, can shoot balls through holes that might appear in this wall and one of your friends is on the other side shooting at you, too.  Some of the squares in this wall are closed, some already have balls going through them and some of these are open for you to shoot through.  You cannot shoot through the ones with balls already going through them or the balls will collide.  The squares in the wall are ports.  Ports provide for communication between one computer (the golfer) and another (the poor guy/girl you’re shooting at) with things called packets (golf balls).  This is the method the internet uses to communicate on ports 1 – 65,535.

Applications on your computer such as Internet Explorer start using ports through a thing called a binding.  To expand on the analogy, you are the owner of the wall of holes.  You have many golfers such as Internet Explorer sending balls through your wall, but only one person can send a ball through one hole at one time.  If more than one person tries to send a ball through one hole at the same time, the balls will collide and neither will get through.  This is what happens when you have two applications trying to get through the same port at the same time.

Since you own the wall, you can also choose when to close holes and which ones to close.  You can also choose which holes are open only to the golfers on your side, which ones are closed only to the golfers on your side, which ones are open only to the other side, which ones are closed only to the other side and which ones are open for balls to fly both ways.  If you leave one of these holes open from the other side to your side, you are more vulnerable to attack by hackers who shoot balls through the wall and try to make them look like legit balls.

Now imagine when a ball comes in it hits one of the shooters on your side of the wall.  The shooter is going to be curious and look at what hit him/her.  This is what happens when one of the applications on your computer receives data.  If a long string of large balls comes in and continually hits one shooter, the shooter faints.  Depending on how long the person(s) on the other side of the wall want the one shooter to be knocked out, they will hit the shooter many times from many different locations.  If there is only one shooter on the other side of the wall aiming at the shooter on your side, the attack he is performing is called a denial of service attack.  If there are many shooters on the other side of the wall aiming at your shooter, the attack they are performing is called a distributed denial of service attack.

The processes described above are happening an infinite number of times every day all over the network known as the Internet.  Hope this helps describe a little bit about how people communicate on the internet.

matt

LEARN MORE

Golf – Wikipedia
TCP and UDP Ports – Wikipedia