The Internet

[fairkatrina]

I have a vague idea of the internet being powered by half a dozen 'supercomputers' that sit around doing nothing but making the internet work. Is that right? It just suddenly dawned on me that I've not got a clue how the wonderful wacky web actually exists.

[rojash]

The internet is a network of networks, and consists of thousands of computers - many of them very similar to the one you are using, and situated all over the world. The whole thing is tied together by routers which send packets of data from machine to machine / router to router over multiple-redundant routes.

[vehelpfulguy]

Think of the internet as being a bit like the telephone system.

The "supercomputers" you talk about are a bit like large international telephone exchanges that route the data from one computer to another.

The actual internet web sites are not held on these "supercomputers" but as rojash says, it is stored on thousands, or maybe millions, of different computers.

If you pick up your phone, and dial a number in Australia, then the telephone system routes you to a phone in Australia.

Well with the internet, when you try to look at a site that exists on a computer in say Australia (an Australian government site for example) then the internet routes you the correct computer in Australia.

The internet runs on a technology called IP (or TCP/IP) and in fact each computer on the internet has its own "phone number" which is its IP address.

You may know Google in the uk as "www.google.co.uk" but the internet knows it as 66.102.9.104

In fact if you put the address below in the top area of your browser it displays the google uk page:

http://66.102.9.104/

In fact you can set up your own internet in your house with just 2 computers (it is called an intranet).

Connect them together, set a web server running on one of them (IIS comes with Windows), add some web pages to that PC, and the other PC could look at the web sites on the first PC.

The "real" internet works on the same principles (but more complex of course)

[Paulst30]

Or you could just say it like i say to my kids

"dad whats the internet?"

Kids, its magic!

Try explaining to a 6 year old how a pc works lol its impossible to make it sound like a teletubbie made it all lol

[lobbert]

could the internet just stop working one day?

[vehelpfulguy]

People do try from time to time to stop the internet working.

They do this with a DOS attack (denial of service attack). This is where they swamp a computer with requests so it is too busy to handle these requests to do anything else.

It would be a bit like someone try to attack your e-mail system by sending you thousands of e-mails. When you logged on to your e-mail system it would try to download these thousands of e-mails and probably crash.

You would have to get your ISP to delete the e-mails from the server and this would cause your e-mail system to be unworkable for a while.

Well a DOS attack works on the same princpal, except that they try to hit the main computers that control the internet traffic.

More on DOS here (but I am not sure I understand it all)

[vehelpfulguy]

whoops, forgot to put the link

http://en.wikipedia.org/wiki/Denial_of_service

In the article above it mentions DNS and DNS servers.

These are the computers that are the Domain Name Servers which make sure a request from a user goes to the right web site.

I mentioned above that www.google.co.uk is also known as 66.102.9.104.

Well this information is held in the Domain Name Servers (along with the details of millions of other web sites).

So when you put www.google.co.uk in your browser, it goes to the Domain Name Server to check for the "real" IP number, and routes you to the google site.

If somone was able to bring down these DNS machines then the internet would stop working.