Windows Server 2008 : Installing the Web Server Role (part 3)

12/9/2010 11:25:27 AM

Understanding IIS 7.0 Role Services

Role services define which specific features and options of the IIS platform are available for use on the local Web server. Once you have installed IIS 7.0 on a computer running Windows Server 2008, you can add components by using Server Manager. When you use Server Manager, you will see a dialog box like the one shown in Figure 1.

Figure 1. Managing Web Server role services in Server Manager

IIS role services are organized into several major areas:

Common HTTP Features
Application Development
Health and Diagnostics
Security
Performance
Management Tools
FTP Publishing Service

The top level of the hierarchy is the Web Server itself. This item represents the core IIS services that are required by the optional components that are also available for installation. Two other items, Management Tools and the FTP Publishing Service, can be installed independently of the Web Server. Each area contains features and options that are related. Several of the items depend on other role services. If you select an item without first selecting its dependencies, you will be given the option to add the required role services automatically. (See Figure 2.)

Figure 2. Including role dependencies when adding a role service

Tip

Note that adding a role service makes it available for use by your Web sites and applications. Additional configuration is sometimes required to take advantage of the service. For example, enabling certain authentication options will not make them automatically apply to all your Web sites.

Default IIS Role Services

As mentioned earlier, the default configuration includes a limited set of functionality. It is appropriate for installations that serve only limited static content and do not need advanced security or development features. In many cases, you will want to enable additional options.

Table 1 lists the role services that are included when you add the Web Server (IIS) server role to the computer.

Table 1. Default Role Services in the Web Server (IIS) Server Role
Group/Category	Feature(s)
Common HTTP Features	Static Content
	Default Document
	Directory Browsing
	HTTP Errors
Health and Diagnostics Features	HTTP Logging
	Request Monitor
Security	Request Filtering
Performance Features	Static Content Compression
Management Tools	IIS Management Console

In the following sections, you’ll learn more about the purpose of these and the many optional role services.

Common HTTP Features

The most important function of the Web Server (IIS) role is to serve HTML Web pages by using the HTTP protocol. The components of the Common HTTP Features group that are available to install are:

Static Content This functionality allows for serving static Web pages to clients, using HTTP. The most common content types are static HTML pages and images. Static content files are usually sent directly to users without any server-side processing.
Default Document This feature allows IIS to return a specific file automatically for a Web site when one is not explicitly requested in the URL. For example, if a user attempts to connect to http://www.contoso.com, the Web server can be configured to return the default.htm file as a response.
Directory Browsing IIS includes built-in functionality for providing basic directory listings to users. When enabled, directory browsing sends information about the files and folders on a Web site to the client’s Web browser. Because users will have the ability to access and download any files to which they have the appropriate permissions, this feature is usually disabled for public Web sites. If the default document feature is enabled and a default document is found, users will not see the directory browsing screen.
HTTP Errors By default, most Web browsers are designed to present an error message automatically to users whenever a problem occurs. For example, if a page cannot be found or if the server is too busy, the Web browser will display this information to the user. To enhance the user experience, IIS can be configured to return custom error pages automatically when these problems occur. The content of the error pages can include contact information for the Web site’s administrator or other details about resolving the problem.
HTTP Redirection The HTTP protocol supports a method of redirecting a request from one site to another. The Web server can be configured to send an HTTP redirect request automatically to a Web user when a specific site is accessed. Site redirection is useful for situations in which a Web site has been relocated to a different URL or when multiple URLs are designed to access the same content.