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Dec
2001
An Eye-Opener!
Don't Panic!
This is just a short article which aims to increase internet
users' awareness of the level of information that can be revealed
by your Internet Browser (e.g Netscape or internet Explorer)
to website owners.
If, like most people, you don't care too much about how the
Interent works, you may still find the information in this article
a bit surprising.
We do not intend to worry you, just inform you! In fact, we
might even convince you that there are many benefits to passing
certain 'non-personal' information to the web sites that you
visit.
What happens when you visit a web page?
Whenever you visit a web page, your computer uses a web address
to find and download some files (text, images, sounds etc.)
from another computer, (a server). It then peices these
files together, and presents the resulting page using a browser
on your computer.
So, for each page that you view on the internet:
(i) Your browser asks for a web page by sending a 'message'
to the server.
(ii) The server responds to your request, and sends a
web page back to you.
What information is passed to the server?
The message that your computer sends to the server contains
quite alot of information, some of it is 'vitally important',
the rest is 'useful'. None of it is personal!
Vitally Important Information
Information that MUST be sent in order for you to view the web
page properly.
For example, your browser MUST send the 'actual web address'
of the web page that you want to view, otherwise the server
won't be able to work out which page to send back. (see below)
Useful Information
Information that may be useful to the server in order
to make sure the page is customized to suit you.
For example, your browser includes some information about itself
within the message to the server - what version is it,
is it Netscape, Internet Explorer, AOL or another make, what
type of files can it cope with etc. (see below)
What could we know about YOU?
| The
web address of the page that you wanted to view |
| /searchqs_latest.htm |
The type of Internet browser that you are using at present |
|
Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)
|
Often
shows the operating system too (e.g Windows)
The spoken-language that you understand. |
| e.g
en-gb
|
Although
it is not particularly accurate, this information may enable
a webmaster to make assumptions about your nationality,
and perhaps location. For example if your computer was set
to read text as 'Chinese', they may assume that you might
be Chinese, or living in China and customize the resulting
web page to suit.
The address of your computer (an IP address).
|
| e.g. 172.188.118.129 |
Not
a real address, of course, but a series of numbers which
point to your computer.
Most webmasters can pick up this information, but it is
unlikely that they will be able to determine any more from
it than the name of the company that you use to connect
to the internet with (an ISP) - e.g AOL, Freeserve,
NTL etc.
If you have been naughty and seriously broken the law, however,
your ISP may be required to trace the IP address
to your telephone and pass on any information that they
hold about you to the appropriate authorities.
A friend of mine, whose website was under attack from a
hacker, used the IP address, in combination with
information on the time of the hack attempt, to get a CCTV
picture of the hacker at work! The culprit was a first year
student sitting in a University computer room. Big Brother
and all that!
Your IP address is mostly used for far less devious
purposes - they help web site owners to count the number
visitors that use their online services.
We know that thousands of people visit our website each
day - we only know this because we can count the number
of unique IP addresses that are used to send requests
to our site. In fact, we only know that 'thousands of computers'
visit us each day, but we assume that the majority of these
computers are being used by people.
The 'refering' web page that sent you to this page!
|
|
e.g http://www.google.co.uk/search?q=info+websites+pickup |
If
you click on a link
on a web page to visit a brand new page, your browser often
remembers the address of the refering page and passes
this address to the new page - even if the two pages are
on two different websites.
This helps website owners to find out which 'buddy' websites
are sending them the most people. We know that the Channel
4 web site refers an awful lot of people to us, because
our records show that many of our visitors where looking
at a page on their server just before visiting us.
Likewise, we can tell which 'search engines' send
us the most visitors. Even better still, because many search
engines carry the search phrase (that was typed in by the
user) in their web addresses, we can tell what our visitors
were searching for when they found our website. |
So why should we care?
We hope to have helped you understand a little bit more about
how the internet works, and perhaps allowed you to see what
a web page looks like from the other side!
As you have discovered, none of your 'personal information'
is sent off around the world willy-nilly by your browser. However,
the next time you use a search engine to find "ways to
spend my vast redundency pay-out'', be aware that this information
is potentially available to every website that you click on!
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