About Configuring Applications (IIS 6.0)
When you create an application, you use IIS Manager to designate the application's starting-point directory, which is also called the application root, in your Web site. You can have more than one application per Web site. The default Web site that is created when you install IIS is an application starting point. Every file and directory that is beneath the starting-point directory in your Web site is considered part of the application until another starting-point directory is found. Thus, you use directory boundaries to define the scope of an application.
To help minimize the attack surface of the server, IIS 6.0 is not installed on Windows Server 2003 by default. When you first install IIS 6.0, it is locked down -- which means that only request handling for static Web pages is enabled, and only the World Wide Web Publishing Service (WWW service) is installed. None of the features that sit on top of IIS are turned on, including ASP, ASP.NET, CGI scripting, FrontPageŽ 2002 Server Extensions from Microsoft, and WebDAV publishing. If you do not enable these features, IIS returns a 404 error. You can enable these features through the Enabling Web Service Extensions node in IIS Manager. For more information about how to troubleshoot 404 errors and other issues, see Troubleshooting in IIS 6.0.
IIS 6.0 supports many types of applications and their configuration options. You can create and then configure your applications for optimal performance and debugging; define a default script language; enable caching, buffering, and parent paths; and associate a file name extension with a type of program. These options can be configured using IIS Manager or the metabase.
An important change in IIS 6.0 that may affect your current Active Server Pages (ASP) applications is that parent paths are not enabled for ASP applications by default. For information on how to enable parent paths, see Configuring ASP Applications.
IIS 6.0 runs in one of two distinct modes of operation: worker process isolation mode and IIS 5.0 isolation mode. Application code runs in an isolated environment, but without the performance penalty of previous versions of IIS. Application isolation is the separation of applications by process boundaries that prevent the applications from affecting one another. Application isolation is configured differently for each of the two IIS isolation modes.
By default, after a clean install of IIS 6.0, IIS runs in worker process isolation mode. In worker process isolation mode, you have the option of pooling application processes. Also, for ASP.NET applications, application configuration is defined through the Web.config or Machine.config files. If you are running in worker process isolation mode, then you must configure the attributes defined in the Machine.config file through IIS.