title: Using Azure AD for customer authentication
body: <p>We are writing an on-premise customer facing web application (.net/mvc) but want to use Azure AD as the authentication method for security reasons and also for possible future reasons. The web app will be (possibly) using forms authentication and authenticate in the controller.</p>
  
  <p>We want to be able to let the customer use any email address they wish.</p>
  
  <p>Is this possible? When I go to manually add someone to AzureAD I can't add someone using user1@myemail.com. We don't want to assign users email addresses in our domain.</p>
  
  <p>Gina</p>