That jumble of
words, numbers, slashes, colons, and squiggles can actually tell you something
about each specific place on the Internet. Just like with the Postal Service,
you can’t get your message there or retrieve a Web page without using the
right address.
The World Wide Web has made using the Internet a breeze. For the
first time people have access to a vast amount of knowledge and information
without the need to remember or type arcane Unix commands and the seemingly
unintelligible mess of Internet addresses.
Today, most Web users access resources by simply clicking their
mouse pointer on hyperlinked words, phrases, or images. (When you pass your
mouse pointer over these links it will change to a pointing finger.) You don’t
need to know the address of the resource’s server, where it is, or where it
comes from.
But what if you read about an interesting Web site in a
newspaper or magazine? Or, a friend gives you an address he thinks you might
want to check out?
To get there you have to type in the actual address in the
address window of your Web browser, and, you have to type it exactly – no
mistakes. This is where the majority of new Internet users run into trouble.
Understanding a little about how Internet addresses are built will help you make
sense of them and, hopefully, this knowledge will alleviate some of those
mistakes.
The string of characters that make up an Internet address are
known as a URL (Universal Resource Locator).
If you want to look at any Internet resource, be it an FTP site, a Gopher menu,
a Web page, or even send an email message, you must either know the URL of the
resource or, as in the case of the World Wide Web, have an imbedded link to the
resource. Those URLs can be a simple string of letters like www.abc.com
or a complex combination of letters, numbers, slashes, and other symbols. In
either case, the URL points to a specific place on the Internet.
Being able to read a URL can be a valuable skill to have when
using the ‘Net. The URL can give you a general idea of where the resource is,
where it originates, and who is responsible for creating it. The address also
hints to the type of resource and whether or not it will be of value to you.
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Internet addresses consist of three separate parts and are read
from left to right. These parts are: The Protocol, the Domain,
and the Path. Because most people access the Internet through the Web,
we’ll use a Web address in our examples. Later, we’ll take look at URLs for
email addresses.
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The Internet uses rules, conventions, and procedures known as Protocols
in order for all the interconnected computers to communicate with each other.
The Internet may consist of millions of computers using any number of operating
systems with data in hundreds of different languages, but the protocols used
over the network to move data from the source to your computer are the same. If
they weren’t, there would simply be no Internet. Each connected computer would
be unable to accept data from the other and nothing would work.
There are many different protocols that govern the Internet.
Lucky for us, they all operate in the background – meaning you, as a user, are
not required to know they are even there to use them. But, by being able to use
them we can send electronic mail, transfer files and view Web pages with ease.
The protocols control the transfer of all this data from one computer to another
automatically with no human intervention.
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The first part of all Web addresses are the letters http
which stand for HyperText Transfer
Protocol. These are the conventions that govern computers that
serve up and deliver Web pages. (That’s where the term server comes from.)
The latest versions of the two popular Web browsers, Netscape
Navigator and Internet Explorer, no longer require users to type http into the
address window to retrieve a Web page – both assume that’s the protocol you
want to use. If, however, you want to use a resource other than Web pages, you
must type the protocol.
The cryptic :// is nothing more than a
separator. It’s purpose is to divide the protocol from the next section.
Again, the time is past that it is necessary to type this into the browser
address window.
The WWW that follows the protocol and separator shows that the
computer is acting as a Web server. Most Web addresses use this as a sort of
standard but it isn’t required. A good example of a Web server that does not
use the WWW designator is Netscape’s home page. It begins with the word home.
(http://home.netscape.com)
After this comes the Domain Name. The domain
name identifies the entity that supports the network server. It also identifies
the general type of organization the entity is. Again, we can use Netscape’s
home page as an example – netscape.com. Netscape is, of course, the
name of the entity that supports and runs the server. The .com (dot com)
indicates the type of organization Netscape is – in this case, a commercial
enterprise.
There are other domain designations, too: .mil (Military)
.edu
(Educational) .net (Network) and, .org (Non-profit organization). The Web is
growing by such leaps and bounds that a shortage of domain names is starting to
become apparent. Soon, more domain designators will be added to this list to
further identify the many different entities that publish and post data on the
Web.
An organization that supports a Web site will create an
introductory page that is sent automatically by default when the site is
accessed by a browser. The default page is called the Home Page.
For instance, if you type www.CalicutNet.com in your browser’s address
window, you’ll see the home page for the CalicutNet Web site. In our case, the
home page file that is automatically sent to your computer is the file index.htm.
The home page can contain basic information about the site and links to other
content on the site.
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Address conventions allow you to further define the address to
the point of retrieving specific files posted on a Web site. Using our example,
you can get the file you are reading now by typing the file name if you know it
– bypassing the Home page. For instance, the page you are reading now is named
webaddresses.htm. To go directly to it you would type the domain, a
separator slash, then the file name:
http://www.CalicutNet.com/News
Each page on a Web site has a special file name and, any
graphics have a file name also. That’s why you will find some Web addresses to
be long-winded and cryptic – they are pointing you to a file on a Web site.
This can even be carried to different directories (or folders) on the Web
site’s server. This is useful if you only want to look at a certain file
bypassing the introductory (home) page and any other pages on the site.
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Most Internet Service Providers set aside an amount of space on
their servers for clients to post a personal page(s). These pages still maintain
the domain name of the entity that supports the server but, lets subscribers
have their own Web address. You can usually tell a personal page because the
separator slash is usually followed by a tilde (~), then the clients
user name.
http://www.domainname.com/~username
Again, this usually points to a default home page. The address
can also point to a specific file within the personal Web site:
http://www.domainname.com/~username/filename.htm
The .htm is known as a file extension and it gives us a
hint as to the type of file it is. In this case, the file name is a hypertext
file. Some hypertext file extensions will have html as the extension.
Both have the same meaning.
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Before you can send off a letter you must know the postal
address and have the address written on the face of the envelope. The same is
true with email – you need to know the address of the party you wish to send
email to. Email addresses follow standard protocols over the Internet in order
for the recipient to get your message.
Email addresses are much simpler than Web addresses and usually
consist of only 2 parts: User Name and the Domain. The user name is the name of
the account an individual has set up with their provider and the provider
supplies the domain. The two sections are separated by the @ (at).
Username@domainname.com
The domain name can be any of the domain designators: .mil,
.net, .org, .edu, and.com.
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Computers, unlike people, cannot think or reason. A person who
reads can notice flaws and mistakes, then, based on past experiences, determine
what corrections need to be made that will render the words, phrases, and
sentences correctly. Computers don’t have this ability yet. Therefore,
everything that the computer interprets must be exact.
That’s the most important factor to consider when working with
Internet addresses. You must get it exactly correct. If you make even a little
mistake in your Web addressing you will either not get the file you want or you
may get an error code (Error 404 File Not Found).
With email addresses the message may be undeliverable and will
bounce back to you. It is possible that you could send your message to someone
other than your intended recipient. In that case, you may completely confuse the
individual who receives it. In either case your message will, in all likelihood,
not get to the person it was intended for. If it’s an important message –
well you get the picture. Remember to get your addresses correct.
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