There are basically three types of authentication modes in ASP.NET – There are basically three types of authentication modes in ASP.NET –
Windows Authentication – windows authentication uses our system credentials for the authentication purpose.
Forms Authentication – This is a form based authentication. Login Control in ASP.NET supports this kind of authentication.
Passport Authentication - Passport authentication lets you to use Microsoft’s passport service to authenticate users of your application.
What are HttpHandlers? ASP.NET programming supports the creation of custom HttpHandler components, which provide an efficient way to process requests that don't return standard HTML-based pages.
E.g. : HttpHandler components are good for situations in which you want to return XML, simple text or binary data to the user.
The easiest way to create a custom HttpHandler component is to create a source file with an .ashx extension. You must then add a @WebHandler directive to the top of the .ashx file with a class definition that implements the IHttpHandler interface.