Q:

Why do I need to configurate Authentication/Authorization in this tuto

I am following this tuto:
https://blogs.msdn.microsoft.com/benjaminperkins/2016/10/20/how-i-connected-a-console-application-to-a-web-api-protected-by-an-azure-active-directory/
I really don't understand why I need the step "configure  Authentication/Authorization for the web apps" in order to make the demo working.
I get a token, send it and the web api receive it. What is this step made for?
The web  api has AuthorizeArribute and a middleware to analyse the token. What more?

A:

App Service Authentication / Authorization is a feature that provides a way for your application to sign in users so that you don't have to change code on the app backend. It provides an easy way to protect your application and work with per-user data. Please click here for more details .
The tutorial tried App Service Authentication/Authorization but not saying that feature should enable if you want to access web api which protected by Azure AD. You could also implement the authentication/authorization with your own code(managed in app), OpenID Connect (ASP.Net OpenID Connect OWIN middleware) could be used to authenticate users from an Azure AD tenant .

