There are millions of computers providing information, that is to say Web Pages and other types of files. They are all connected together by telephone type or fibre optic cables. Each of those computers has one or more IP (Internet Protocol) addresses associated with it.

When you use a browser program (Internet Explorer or Netscape or something similar) on your computer, before you can get any Web Pages, you need to get connected to "the Internet". That is to say the cables described in the first paragraph. It has several nicknames, "the Backbone" and "the Cloud" are just two. You achieve that connection by using the services of an ISP (Internet Service Provider). ISP's have one or more computers connected to the Backbone. You connect your computer to their computer and then they connect you to the Backbone.

There are several ways in which you can connect your computer to your ISP. You can use the PSTN (Public Service Telephone Network) - "the plain ordinary phone system". You can use a Radio connection. You can use a Satelite connection. I am sure that there are other methods too - but the three shown give you the idea.

Once you have established the connection to your ISP and thence to the Backbone, you have a computer connected to the Internet and therefore your computer is given a dynamically allocated IP address.

 

That is the story of IP addresses !!

Now we will go further and talk about how they are used. In very simple terms, information (also known as data) is sent around the Backbone. To describe it in simple terms, your ISP assembles a Data Packet. That Packet contains three basic parts:-

• The IP address sending the packet.
• The IP address that the packet is being sent to.
• The data being sent (this may be a question, a request, a reply, an answer).

The ISP throws the packet out onto the Backbone where it whizzes around untill another ISP spots it whizzing past and says "that is for me" and grabs it. It then sends a packet back saying "I have got it - hang on a moment and then I will send a proper reply". And so it goes on !!

Of course the process is much more sophisticated than this - BUT - remember this is a very simple non technical description. Hopefully it will have put a picture in your mind.

 

But I do not put IP addresses into my browser !!

That is true but you could have !! Probably the address that you have used to get to this page is:-
http://www.ibrus.com/writings/ipinfo.htm
but you could have used
http://195.99.184.152/writings/ipinfo.htm
they are two different ways of saying the same thing. When you put either of them into the address in you browser and press Enter, it will be sent to you ISP. The ISP will translate that into a packet looking like:-

• The IP address sending the packet. That is the address that you have been given
• The IP address that the packet is being sent to. 195.99.184.152
• The data being sent (this may be a question, a request, a reply, an answer). It will say "I want the contents of the file called '/writings/ipinfo.htm' on your computer sent back to me in http format"

Eventually the http (Hyper Text Transfer Protocol) code for this page will be sent back to you in a packet.

You will see that it is only the part between the "//" and the first "/" that is the address. Many browsers will add the "http://" at the front for you, if you leave it out.

How does the ISP translate "www.ibrus.com" into "195.99.184.152" ?? Well, it may have the information on its own computers but if it does not, it will send a packet to a site that has a registration database saying "Please give me an IP address for this site". You could imagine it as being similar to getting a telephone number, first you see if you have got the number in your own address book - if not, you go to directory enquiries.

 

Data Packets are the way the internet works !!

It would be wrong of me to end this without making you aware that folk can send unsolicited packets to your IP address. Your computer must deal with such packets !!

Now a step further. Evil, nasty, unkind folk could send packets that tell your computer to do things to itself that damage your computer's ability to function. Even to send EMail messages to EMail addresses that it finds on your computer. This is known as hackers sending viruses.
Viruses can get onto your computer by several means:-

• On floppy discs
• On CDs
• In EMails
• In unsolicited data packets

So do beware !!

Clever folk elsewhere connected to the internet, may have a look at files that you have on your computer - they are generally known as Hackers. Even cleverer folk may be able to put files onto your computer. They may even be viruses that make your computer feel very poorly, or Trojan Horses that report your computer activity back to their owner.

 

Not very nice is it !! You can check how secure you are by visiting grc.com. When you get there, follow the links to "TestMyShields" when you have done that, try "ProbingMyPorts" - I hope you are not dissapointed !!

 

If you have not already, you can make yourself safer by erecting a firewall around your computer. One that I recommend is called ZoneAlarm. You can pay for a copy or download it for free from http://www.zonelabs.com I really do urge you to get a copy !!

 

After you have installed it, re-visit grc.com.

 

If you have not already got one, you would be well advised to get an Anti Virus program for your PC. I use a program called Norton AntiVirus - I saw it advertised today for just under £30.00 plus VAT. There are however lots of such programs available - I do not have the knowledge or expertise to offer an opinion on which is best.

 

That's it !!

I hope that you have enjoyed reading this page and have found it useful and/or informative - BUT - remember, this is a very simple non technical description. Hopefully it will have put a picture in your mind. If you want to learn more about this, there are books and websites that will tell you about it. If you cannot find anything, let me know and I will try to help you. If you find any really good books or places to learn more - please tell me.

 

Thank you.