The ASP.NET framework uses this authentication module automatically when no other authentication module is specified in the current context (for example, when you set <authentication mode="None"> in the web.config file. This is similar to how many traditional ASP applications work. IIS authentication is still used and access to local system resources is provided in the context of a local system process account (or the IUSR_MACHINENAME account) according to the IIS settings. However, ASP.NET page requests will not require additional authentication.

public sealed class DefaultAuthenticationModule : System.Web.IHttpModule {
// Public Constructors
   public DefaultAuthenticationModule( );
// Public Instance Methods
   public void Dispose( );                           // implements System.Web.IHttpModule
   public void Init(System.Web.HttpApplication app); // implements System.Web.IHttpModule
// Events
   public event DefaultAuthenticationEventHandler Authenticate;
}