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.
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.)
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.
Although
these Common HTTP Features can be added, the specific behavior of each
IIS Web site will be based on its content and configuration settings.