title: Can you use an email address as the login with Active Directory and SharePoint?
body: <p>Assuming email addresses are all different, so not from one or two single email suffixes.</p>
  
  <p>I know there is UPN login, but I believe that to be with predefined UPN Suffixes, not 1000s of unique ones.</p>
  
  <p>There is also ADFS type stuff.</p>