Welcome to the Internet

A protocol is a sequence of steps that computers take when exchanging information with each other. The basic protocol for the Internet is TCP/IP.
ne computer by itself is a useful tool. You can work with and store a great deal of information. A network, or group of computers working together, is an even greater tool. You and other people can share and work with each other's information in a variety of ways. If a network can exchange information with other networks through a protocol called TCP/IP, it is part of the Internet. At its simplest, the Internet is a network of networks. No one person or company runs the Internet. Because of t his design, the information available on the Internet changes constantly, and new computers are continually added to the network, which provides an ever-growing source of information.

Through the Internet people can:

Web sites are collections of documents that can be hypertext, graphics, sounds, movies, and more. Often they contain links to other web documents, perhaps at other web sites. To a user, it hardly matters that some documents are at different sites--they are all merely a click away. All the web sites in the world are known collectively as the World Wide Web (often referred to as "WWW" or simply "the web"). You access the web with a web browser like the one that's part of Netscape Navigator.

If a company maintains an internal network of web sites, email, and other Internet services, this structure is called an intranet. An intranet is a particularly useful way to disseminate information within a company. Intranets can contain such information as Human Resources benefits policies, sales and marketing product details, company phone lists, product plans, and various types of online forms.

Usually, an intranet is kept behind a company's firewall, meaning that only people in the company can access it.

Web basics

The web is based on a client/server relationship. The client program (a web browser) requests information, and the server program supplies it. When clients on the Internet connect to servers to send email, read newsgroups, or visit web sites, they communicate using other protocols in addition to TCP/IP. When multiple protocols are used in communication, they are often thought of as layers. That is, TCP/IP is the bottom layer in Internet communication, and it specifies exactly how all digital data is transf erred from one computer to another. The next layer above might be HTTP (HyperText Transport Protocol), which specifies what type of communication and information is sent between a web site and a web browser. HTTP is what makes web servers and web browsers speak the same language; TCP/IP is what makes sure the messages are sent back and forth reliably.

Other protocols that work "on top" of TCP/IP are:

The various protocols are handled transparently by the client and server software. The only time a person sees what protocol they're using is when they type an Internet address, called a URL, into the Location field of their browser.

Understanding URLs

To get information from the Internet, you need to know the address of the information. These addresses are called Uniform Resource Locators (URLs). URLs are in the format protocol://computer/directory/file. An example of a URL is http://www.danishfurniture.com/products/orderform.html.

Most files on the web have the extension html or htm. The HTML file format stands for HyperText Markup Language.
The protocol to access the web is HTTP, so all web URLs begin with http://, like the preceding example. The rest of the example URL is straightforward--the machine name is www.danishfurniture.com, the directory we want on that computer is products, and the file in question is orderform.html. Typing that URL into Navigator's Location field would display the file orderform.html, from www.danishfurniture.com, in the products directory. The file would have been sent from the server to the client through HTTP.

Note
On the Internet, computer names are actually numbers, like this computer name: 198.95.251.30. This is called a computer's Internet Protocol address, or IP address. To make Internet navigation easier for humans, each IP address also has a name associated with it, like home.netscape.com, or www.danishfurniture.com. The words you type into the location field in Netscape Navigator are automatically translated to numbers by a special program called the Domain Name System (or DNS), which is maintai ned by your Internet provider or IS department.

Understanding web servers

In the previous section's example, a computer named www.danishfurniture.com held a file in one of its directories. This in itself is not unusual--every computer contains files in directories. What makes www.danishfurniture.com different from other computers is that it can serve its documents to clients when requested. The computer is able to do this because it is running a server program that "speaks" HTTP, and it is physically connected to a TCP/IP-based network.

Sometimes the word "server" is used to mean the machine that serves the documents, but in these discussions, "server" refers to the installed program.
When you install a Netscape server, you specify a directory to contain all the files you want to serve to clients. All directories and subdirectories below that main content directory are available to clients. As mentioned previously, the most basic type of content at a web site is HTML files. Additionally, web sites can contain programs that perform special tasks for people who visit them. For example, a web site might have a program that looks up stock prices, based on information a user fills out in an HTML form. Further, some web sites can hold programs that actually run on client computers, when they connect to the server.

The uses and abilities of web sites are virtually limitless. As the definition of HTML grows, so does its ability to present more varied and dynamic information. And with Java, the programming language that was created to run programs over the Internet, you have the power to make a web site into almost whatever you want. On the web there are shopping malls, interactive stories, encyclopedias, video games, banks, and much more.

The Netscape Enterprise Server

The following features are a partial list of what the Netscape Enterprise Server offers: