CHAPTER 2: Understanding the Internet and Internet Services

### CHAPTER 2:

# Understanding the Internet and Internet Services

What is the Internet?
What is an Intranet?
What is Internet Explorer?
What are Peer Web Services?

Prior to planning and implementing a Web site on a computer running Windows NT Workstation, you should understand each of the components required to establish a Web site.

This chapter answers the following questions:

- What is the Internet?

- What is an intranet?

- What is Internet Explorer?

- What are Peer Web Services?

# What is the Internet?

The Internet is a global network of computers that communicate using a common language. It is similar to the international telephone system — no one owns or controls the whole thing, but it is connected in a way that makes it work like one big network.

The World Wide Web (WWW) gives you a graphical, easy-to-navigate interface for looking at documents on the Internet. These documents, as well as the links between them, comprise a “web” of information.

Files, or “pages,” on the Web are interconnected. You connect to other pages by clicking special text or graphics, which are called hyperlinks.

Pages can contain news, images, movies, sounds — just about anything. These pages can be located on computers anywhere in the world. When you are connected to the Web, you have equal access to information worldwide.

Hyperlinks are words and graphics that have Web addresses embedded in them. By clicking a hyperlink, you jump to a particular page in a particular Web site. You can easily identify a hyperlink. Hyperlink text is usually a different color from the rest of the text on a Web page, and hyperlink graphics often have a colored border.

Each Web page, including a Web site’s home page, has a unique address called a Uniform Resource Locator (URL), for example, http://www.microsoft.com/home.htm. Domain Name System (DNS) names are used on the Internet.

# What is an Intranet?

In this book, “intranet” refers to any TCP/IP network that is not connected to the Internet. An intranet can be with the same features and services found on the Internet, such as serving hypertext pages (which can contain text, hyperlinks, images, and sounds), responding to Web client requests for information, and accessing a database.

# What is Internet Explorer?

Microsoft Internet Explorer is a Web browser. Just as Microsoft® Word is a tool to do word processing, or Microsoft Excel is a tool to do spreadsheets and calculations, Internet Explorer is a browser, or a tool for navigating and accessing information on the Web.

The toolbar provides a range of detailed functions and commands for managing the browser. The address bar below the toolbar displays the current Web site address being accessed. To go to a new Web site, you type the site’s URL directly into the white space on this bar. When you have finished typing, press ENTER on your keyboard.

The Windows NT Workstation operating system includes a version of Microsoft Internet Explorer. Other versions of Internet Explorer are available for each Windows operating system: Windows for Workgroups, Windows version 3.1, and Windows 95.

# What are Peer Web Services?

Microsoft Peer Web Services make it easy for you to create a personal Web site on your Windows NT workstation. With Peer Web Services installed, you can share information over your corporate intranet as easily as you share files. Other network users can access your files using Web browsers. Your workstation uses the HyperText Transport protocol (HTTP) to respond to browser requests. In addition, your workstation can be configured to provide FTP and gopher services.

Using Peer Web Services, your workstation becomes a personal Web server that can publish Web pages to intranet users. If your workstation or network is connected to the Internet, you can even publish personal Web pages to Internet users. Just as sharing files does not mean your workstation becomes a dedicated file server, publishing Web pages does not mean your workstation becomes a dedicated Internet server. If you need a dedicated Internet server with advanced administration capabilities and the ability to respond to many simultaneous connections, you should use Microsoft Internet Information Server, which is included with Windows NT Server version 4.0. See the Microsoft home page (http://www.microsoft.com) for more information on Internet Information Server.

## What Can I Do with Peer Web Services?

With Peer Web Services, you can publish a personal Web site from your desktop. Personal Web sites are useful for workgroup information that you want to make available to all members of your group, or personal home pages that you want to make available on an intranet or the Internet. Peer Web Services are integrated into the Windows NT Workstation operating system and take full advantage of its networking and security features.

The creative possibilities of what you can offer on a personal Web site are endless. Some familiar uses are to:

- Publish a personal home page.

- Publish project documents, such as schedules, memos, and reports.

- Publish interactive programs.

- Provide your remote sales force easy access to your sales database.

- Use an order-tracking database.

With Peer Web Services, you can also develop and test Internet Server Application Programming Interface (ISAPI) applications on a computer running Windows NT Workstation. You can then install and run the ISAPI application on a computer running Windows NT Server and Internet Information Server.

## How Do Peer Web Services Work?

The Web is fundamentally a system of requests and responses. Using Peer Web Services, your workstation becomes a Web server that responds to Web browser requests for information. Your workstation uses the WWW service, one of the Peer Web Services, to listen for requests from users on the network.

## Browser Requests

Browser request syntax determines what the Web server does with a request. Requests are in the form of a URL.

### URL Syntax

URL syntax is a specific sequence of protocol, domain name, and path to the requested information, as described in the following table. Protocol is the application used to gain access to information; for example, HyperText Transport Protocol (HTTP). Domain name is the name registered in DNS. The path is the directory path to the requested information on the file system.

Protocol | Domain Name | Path to Information

http:// | www.microsoft.com | /backoffice

https:// (secure HTTP) | www.company.com | /catalog/orders.htm

gopher:// | gopher.college.edu | /research/astronomy/index.htm

ftp:// | orion.bureau.gov | /stars/alpha quadrant/starlist.txt

### Request Syntax

Just as Microsoft Word documents use the convention Filename.doc, and programs use the convention Programname.exe, the path to information determines whether the request is for a static HyperText Markup Language (HTML) page, for a dynamic HTML page, or for a directory listing. Sometimes the path includes parameters, or data, the Web server processes before returning a dynamic page.

In all cases the Web server replies with an HTML page (or an error message). Example request types are listed in the following table:

Request Type | URL

Static HTML page | http://www.microsoft.com/backoffice/home.htm

ISAPI application | http://www.msn.com/custom/page1.dll?CUST=on

Internet Database Connector | http://www.microsoft.com/feedback/input.idc

CGI script | http://www.company.com/calculator/add.pl?2.2

Directory listing | ftp://orion.nasa.gov/stars/alpha quadrant/list

## Web Server Response

The Web server running on your workstation usually responds to client browser requests by returning an HTML page. The returned page can be one of three types: a static HTML page, a dynamic HTML page, or a directory listing page.

### Static Pages

Static pages are static HTML pages that are prepared in advance of the request. The Web server returns the HTML pages to the user, but takes no special action. The user requests a static page by typing in a URL (in the following illustration, http://www.company.com/home.htm) or by clicking a link pointing to a URL. The URL request is sent to the WWW service. The service responds by returning the static HTML page.

### Dynamic Pages

Dynamic pages are created in response to a user’s request. The user requests a dynamic page by clicking a link pointing to a URL, or by clicking a button on a form, which in turn sends the data in the form to the Web server. The server uses any data supplied by the user to run the specified script or application or to query or post data to a database. The results are returned to the user in an HTML page.

The following illustration shows how a user can send a query to an Internet Server API (ISAPI) application that adds two numbers. The user types the two numbers to be added, then clicks a button, which in turn sends the two numbers to the application. The application adds the numbers, then returns the results to the user in an HTML page.

The following illustration shows a user posting an order to a database using the Internet Database Connector. The user completes a form, then clicks a button, which in turn sends the data in the form to the Web server. The server posts the data to a database, then confirms the order by sending an HTML page.

### Directory Listings

If users might send queries without specifying a particular file, you might want to configure Peer Web Services for directory browsing. If directory browsing is configured, a directory listing (a hypertext version of a File Manager listing) is returned to the user in the form of an HTML page. The user can then jump to the appropriate file by clicking it in the directory listing.

In summary, the Web server responds to user requests with an HTML page. This page can be a static page that is already prepared, or it can be generated in response to information that the user provides, or it can be a directory listing that is created automatically from a listing of the available files and directories.

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