auth.models.User.is_active

is_active

Boolean. Designates whether this user account should be considered active. We recommend that you set this flag to False instead of deleting accounts; that way, if your applications have any foreign keys to users, the foreign keys won’t break.

This doesn’t necessarily control whether or not the user can log in. Authentication backends aren’t required to check for the is_active flag but the default backend (ModelBackend) and the RemoteUserBackend do. You can use AllowAllUsersModelBackend or AllowAllUsersRemoteUserBackend if you want to allow inactive users to login. In this case, you’ll also want to customize the AuthenticationForm used by the login() view as it rejects inactive users. Be aware that the permission-checking methods such as has_perm() and the authentication in the Django admin all return False for inactive users.