You're right it should be interchangeable but that's not how the DNN process looks at it. When a user logs in (either manually or automatically) it checks if the username exists already in the database and adds them if it doesn't. So "domain\user" and user@domain are considered different users. What I need to do is add a setting for administrators to choose how they want their users stored in the database which is easy enough but then I need to be able to change all the current users in the database. I'm going on memory but I don't think the current package installer will handle sql scripts being added but that will change with the release of DNN 5.

You're right that automatically logged in users have a random password generated for their account but if they use the Windows Login option and manually login through that one it checks the password against the AD and updates the password in the DNN database. If they try to login with "Domain\User" under the standard DNN login against the random password then, yes, it will fail.

Yes I could but there's more to it than that. If I put an drop down box in the settings page for "Store Usernames In Which Format?:" and put the following options in:

1. Domain\Username
2. Username@domain.com
3. Just username

I have to account/program for user's that are already in the database. I don't think the package installer, in the state that is in DNN 4, installs SQL procedures into the database so I haven't been able to make add those options but that will change with DNN 5 as the package installer that's currently used just for authentication providers will be used for all modules/skins/etc.

Now when logging in fails under Windows login, is there anything significant posted to the Event Viewer in your DNN install? I really can't understand why that's not working for you but entering your email account does. It's just the code authenticating the username entered against the AD.

Check your actual AD. I'd be willing to bet that at the top of the tree it's listed as just domain and not domain.com.

I wasn't talking about giving the users the option of how their username is stored but the administrators of the site. Like you mentioned, all your users connect to network resources using user@domain.com but mine all connect using domain\username so I would want to give the administrator the option of how the username is stored. Your scenario of the same username across multi domains is one of the reasons why I haven't implemented the ability to strip the domain from the account (also have to consider portals that allow regular registrations). The code to strip the domain from the username is actually there already but is hidden until I find a suitable solution.

If you open the Users table and find your user account you can change the IsSuperUser flag to a 1 or True (depending on what version of SQL you're using) to promote your user to Host status.