Using the Internet today with a web browser is easy. Most of the time Internet surfers don't need to know the "address" or location of whichever Net resource you are using or where it comes from.

Today's browsers fully exploit "point and click" use of the mouse. On most web pages you simply click on a word, button or picture to get to another web page, download a file or send an email message.

But then there are those sites that you hear, read or are told about. If you read about an interesting Web site or you want to visit the web site your cousin just set up with pictures of the new baby, you might not have a link to click on.

Trying to get to a new Internet site can be frustrating. There is no room for even the slightest typing error with computers and web addresses. Let's see if a little understanding of how web addresses are put together might make it a little less frustrating trying to get to new web sites.

Introducing the Earl of URL ...

The string of characters that makes up an Internet address is known as a URL (Universal Resource Locator, pronounced like "Earl").

An URL can be as simple as http://www.pcworld.com or a fistful of numbers, letters, symbols and punctuation 50 or more characters long. Regardless of its form, an URL points to a specific place and resource on the Internet.

Understanding what makes up an URL will give you some general idea of the "who, what, and where" of any Web address you are interested in and may help you guess if it will be something you are interested in.

Piece by Piece
All Internet addresses consist of several parts. They are from left to right:
 

Protocol

protocol-separator

Domain name

path/filename

Protocols
The Internet is a diverse network of diverse networks. It brings together and links virtually every type of computer running every operating system ever invented using too numerous to mention programming languages. To get this eclectic zoo to communicate effectively there are some agreed upon "rules of the game" known as protocols.

Protocols are sets of rules and conventions established to govern just about every aspect of Internet intercommunication. Without these protocols and the voluntary (yet compulsory) support of these protocols the Internet would not be possible. If a computer or computer network wants to interconnect to the Net, it must follow the protocols.

There are well defined protocols for virtually every task of intercommunication, from sending email, downloading and uploading files, browsing web pages, delivering graphics, etc. Fortunately, you - as a web surfer -  don't have to know much about how they work to use them. In fact, you don't even have to know that they exist, but knowing something about them may make the ride more enjoyable.

The disappearing HTTP...
Web page addresses - URLs - all start with "http" which stands for HyperText Transfer Protocol. This particular protocol is the set of rules and specifications which must be used by any type of computer connected to the Net to process, serve, transport and deliver Web pages.

Recent versions of both of the two leading browsers, Microsoft's Internet Explorer and
Netscape's Navigator now assume that "http" is there if it is left off a web address. They figure you meant to put it there if you just type www.pcworld.com instead of http://www.pcworld.com.

All Secure
There is one variation of the HTTP protocol that is used for secured data transmission such as for web site which process credit cards and password protected pages. These web pages use encryption to protect the data transferred to and from the user from any interceptors. When a web page is using this encryption technology, the protocol changes from "http" to "https". If you ever want to use your credit card on the Internet, go ahead, it's safe, just make sure the web page starts with https://.

File Transfer Protocol
The protocol which handles transferring files between any two computers on the Internet is called the File Transfer Protocol. You may see links on a web page inviting you to download a file. Look at the address when you click on the link, often it will not start with "http" but with "ftp". For example
ftp://www.nw.com takes you to a very different place than http://www.nw.com.

Colon-slash-slash
The "://" is only there to separate the protocol from the rest of the web address. On the new browsers you don't have to type it (nor http) if you just want to browse a web page.

Double-ewe Double-ewe Double-ewe
What a mouthful. Wouldn't it have been nice if the the early designers had decided to use "web" instead of "www"?

Surely, web.pcworld.com is just as easy as www.pcworld.com but, oh, so much easier to say. Nine syllables we can do without saying a hundred times a day. Why don't we all agree to say "web dot" and save a few hundred hours of our lives for something better? Just start doing it and see if it catches on.

Domain Names - What's your Dotcom?
The Domain name tells you the web server's organizational name. It also can tell you something about where the server is or what type of organization runs it.

The last (rightmost) part of the Domain Name is also called the High level domain qualifier. The one you are likely most familiar with ".com" (dot com) means that the web server is a commercial entity.

The other main high level Domain designators include:
 

Outside of the U.S. the high level domain is usually one of the standardized two-digit country codes like ".eg" for Egypt. (If you want to see a list of all the two digit country codes, see:
http://www.y2kegypt.com/netcodes.htm.

Get 'em while they're hot...
There are not enough domain names to go around for everyone so the Web powers that be have - almost - agreed on an expanded set of high level qualifiers like .nom, .arts, .rec that will make more web addresses available. Pretty soon, every will want to know your "Dot NOM", "nom" standing for "nomial" for personal names.

More hidden stuff
We finally get to the web page path and filename and it most cases we don't use it. Each web page does have a path and filename, of course, it is just that most times, the address you see when first visiting a web site is the default home page. You don't have to type the path/filename and your web browser doesn't show them.

For example if you type http://www.presidency.gov.eg (Home Page of the Egyptian Presidency) into your browser, you have filled in the first three parts of the Internet address. It works, but where is the "path/filename"?

In this case, it is "/index.html", so the full qualified web page address is:

Like most web servers (those are the computer programs which contain and host web sites), this one hosting the Egyptian Presidency site has a rule that if you do not specify a path/filename it will try a default value of  "/index.html" . Unfortunately, not every web server uses the same default(s) or uses them in the same order.

Usually Web servers will look for various possible default files in a particular order and serve up to the user the first one it finds in the list.

Some common default web page names used/required by web servers include:

• index.htm
• index.shtml
• default.htm or default.html
• welcome.htm or welcome.html

~MyPage
Many Internet Service Providers (ISPs) provide a small space for subscribers to put up their own web site. With these you can have a web page without setting up your own domain name.

These free web sites are often identifiable by the tilde (~) character in their name. For example, the web address for a free subscriber web page might be:

http://www.greatisp.com/~alincoln

Other Flavors of Web Servers
There are many programming systems which provide web programmers with extensive advanced capabilities to develop interactive and dynamic web sites. Often these web pages use features provided by specific web server packages and "pre-processors". Some of the famous ones include Cold Fusion, MS Active Server, Miva scripting and others.

You can recognize a Cold Fusion web page if the filename ends in ".cfm" rather than "htm" or "html" and similarly an Active Server Page will end in ".asp". and .shtml is sometimes used for preprocessing systems call "server side includes".

Email Addresses
Email addresses are far simpler than web page resources and  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 email provider and the provider supplies the domain. The two sections are separated by the @ (at sign).
For example: kilenm@bigfoot.com.

Perfection ... or else
Computers are merciless proof readers and spell checkers. One stray character, one extra blank space and your nearly perfect web address will send your web browser or email message bouncing to the great Internet trash can.

Normally, email that can't be delivered for any reason will be returned to you. This is known as a "bounced" email message. A worse case is if you send an email message to a proper email address - but the wrong one! You may never know that your intended recipient never got the message you tried to send them and you may have firmly confused someone who is wondering who you are and why you sent them your life's story.

So, hopefully you are now armed with a little better understanding of where you are when you are surfing the Net. Happy Travels!

Feedback
Hate this column? Love this column? Have ideas for what should be covered - Send suggestions for Internet Basics topics by email to basics@y2kegypt.com. The best suggestion gets a PC World-Egypt T-shirt! Kilen Matthews (kilenm@bigfoot.com) is an Internet and Year 2000 Consultant for Y2KEgypt LLC (http://ww.y2kegypt.com).