I have an ASP.NET app. that has an internal users list in the database that it checks upon authentication. I want to allow users to authenticate on it also with their domain-controller credentials. For example let's say user1 has a domain username of firstname.lastname@example.org; and when he does authenticate this way, I want this login to impersonate his equivalent DB user "dbuser1", thus authenticating him successfully on our asp.net app.
Any idea how this can be done? (while simultaneously allowing login from dbuser1 or email@example.com )