CHAPTER 2

Understanding the Internet and Internet Services

What is the Internet?
What is an Intranet?
What is Internet Explorer?
What is Internet Information Server?

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

This chapter answers the following questions:

- What is the Internet?

- What is an intranet?

- What is Internet Explorer?

- What is Internet Information Server?

# 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 or simply the Web) 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 text, 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 or 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. The URL specifies the name of the computer on which the page is stored and the exact path to the page.

# What is an Intranet?

In this book, intranet refers to any TCP/IP network that is not connected to the Internet but uses Internet communication standards and tools to provide information to users on the private network. For example, a company can set up Web servers that are accessible only by employees to publish company newsletters, sales figures, and other corporate documents. Employees access information by using Web browsers.

Web servers can be configured to provide an intranet 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. In this guide, these publishing services are described as “Internet services” whether they are running on an intranet or on the Internet.

# What is Internet Explorer?

Microsoft Internet Explorer is a Web browser. Just as Microsoft® Word is a tool to create and format documents, or Microsoft® Excel is a tool to create spreadsheets and perform calculations, Internet Explorer is a tool to navigate and access, or “browse,” information on the Web.

The Internet Explorer toolbar provides a range of detailed functions and commands for managing the browser. The address bar below the toolbar displays the address of the current Web page. To go to a new Web page, you type the page’s URL directly into the white space on this bar and then press ENTER on your keyboard. You can also go to a new page by clicking a hyperlink that jumps to the new page.

The Microsoft Windows NT® operating system includes Internet Explorer for Windows NT. Internet Explorer is also available for Windows® for Workgroups, Windows version 3.1, and Windows 95.

# What is Internet Information Server?

Microsoft® Internet Information Server is a Web server that enables you to publish information on a corporate intranet or on the Internet. Internet Information Server transmits information by using the Hypertext Transfer Protocol (HTTP). Internet Information Server can also be configured to provide File Transfer Protocol (FTP) and gopher services. The FTP service enables users to transfer files to and from your Web site. The gopher service uses a menu-driven protocol for locating documents. The gopher protocol has been largely superseded by the HTTP protocol.

## What Can I Do with Internet Information Server?

The creative possibilities of what you can offer on an Internet Information Server Web site are endless. Some familiar uses are to:

- Publish a home page on the Internet for your business featuring a newsletter, sales information, or employment opportunities.

- Publish a catalog and take orders from customers.

- Publish interactive programs.

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

- Use an order-tracking database.

## How Does Internet Information Server Work?

The Web is fundamentally a system of requests and responses. Web browsers request information by sending a URL to a Web server. The Web server responds by returning a Hypertext Markup Language (HTML) page.

The HTML page can be a static page that has already been formatted and stored in the Web site, a page that the server dynamically creates in response to information provided by the user, or a page that lists the available files and folders on the Web site.

### Web Browser URL Request

Every page on an intranet or on the Internet has a unique URL that identifies it. Web browsers request a page by sending a URL to a Web server. The server uses the information in the URL to locate and display the page.

URL syntax is a specific sequence of protocol, domain name, and path to the requested information. The protocol is the communication method used to gain access to information; for example, Hypertext Transport Protocol (HTTP). Internet Information Server supports the HTTP, FTP, and gopher protocols. The domain name is the Domain Name System (DNS) name of the computer that contains the information. The path is the path to the requested information on the computer. The following table shows examples of different URLs:

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

A URL can also contain information that the Web server must process before returning a page. The data is added to the end of the path. The Web server passes the data to a program or a script for processing and returns the results in a Web page. 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
Common Gateway Interface (CGI) script | http://www.company.com/calculator/add.pl?2.2

### Web Server Response

A Web server responds to a Web browser request 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 an URL (in the following illustration, http://www.company.com/home.htm) or by clicking a link pointing to an URL. The URL request is sent to the server. The server responds by returning the static HTML page.

#### Dynamic Pages

Dynamic pages are created in response to a user’s request. A Web browser collects information by presenting a page with text boxes, menus, and check boxes that the user fills in or selects. When the user clicks a button on a form, the data from the form is sent to the Web server. The server either passes the data to a script or application to be processed, or it queries or posts data to a database. The server returns the results 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 Web server. The Web server calls the ISAPI application to add 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 server. The server posts the data to a database, then confirms the order by sending an HTML page.

For information about using scripts, applications, or database queries to create dynamic HTML pages, see Chapter 8, “Publishing Information and Applications.”

#### Directory Listing

If users might send queries without specifying a particular file, you can either create a default document for a Web site or for a particular directory, or you can configure your server for directory browsing. If no default document is created for a directory and directory browsing is configured, a directory listing (a hypertext version of a Windows Explorer or 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.

Rather than using directory listings, you can provide a default document. For more information on default documents, see Chapter 6, “Planning Your Content Directories and Virtual Servers.”

## How Do I Use Internet Information Server?

Internet Information Server is flexible enough to perform many important functions for your organization. It is scalable from supporting a single-server site to supporting large multi-server installations. For example, www.microsoft.com and www.msn.com are among the busiest Web sites on the Internet today, and both use multiple servers running Microsoft Internet Information Server.

One of the primary factors that determines the configuration and use of Internet Information Server is whether it will be used internally by employees on your intranet, or if it will be connected to the Internet.

The following scenarios are intended to help you understand the range of possibilities for using Internet Information Server.

### Intranet Scenarios

Internet Information Server integrates well into almost any existing environment. Because Internet Information Server integrates Windows NT security and networking, you can often add the software to an existing computer and use existing user accounts. It is not necessary to use a dedicated computer to run Internet Information Server.

For example, in a small workgroup you can add Internet Information Server to an existing file and print server. The workgroup’s Web server can host personal Web-style pages, customized workgroup applications, serve as an interface to the workgroup’s Structured Query Language (SQL) database, or use Remote Access Service (RAS) to provide dial-up access to the workgroup’s resources from remote sites.

In a larger business with multiple departments or workgroups, each department might run Internet Information Server on an existing file server for workgroup-specific information. A central information server might be used for company-wide information, such as an employee manual or company directory.

### Internet Scenarios

Internet Information Server can function as a simple dedicated Web server on the Internet, as shown in the following illustration.

In larger sites you can provide access from your internal network to the Internet Information Server, allowing employees to browse the server or to use authoring tools, such as Microsoft FrontPage™, to create content for your server.

Internet Information Server’s integration with all of the Windows NT services can also create servers with multiple functions. For example, a company with sites in different parts of the world can use Internet Information Server to provide communication between sites, with the added flexiblity of Internet access. You can even add RAS to an Internet Information Server to provide dial-up access to your intranet or the Internet.

Note Many scenarios for connecting to the Internet involve third-party routers or security devices that filter network packets between your computer and the Internet. Routers and other security devices are not indicated in the preceding illustrations.

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