Classic ASP global.asa file equivalent in Asp.Net

This explains the equivalent of global.asa of classic ASP in Asp.Net

In ASP, we use global.asa file to have application and session level data and events to be defined which is shared by all the users using the website.

Asp.Net equivalent of this global.asa of classic ASP is global.asax which contains application level and session level events. This global.asax file in Asp.Net is an optional file and is required only if you wanted to have any application and session level events in the web application. This file is compiled into dynamically generated .Net class which will be derived from HttpApplication base class so that any url request is rejected.