What is impersonation in ASP.NET?
By default, the ASP.NET executes in the security context of a restricted user account on the local machine. Sometimes you require to access network resources like file on a shared drive that requires additional permissions. One way to overcome this restriction is to use the impersonation. With impersonation, the ASP.NET can execute the request using the identity of the client who is making the request, or ASP.NET can impersonate a specific account you specify in web.config.