My goal is to setup DNN for an external site and hookup to an existing AD. I've installed 4.08.03 ( w. AD ver. 1...3) 

I followed the setup instructions and everything says OK..under host. However, when logout and I try to login with an existing AD account as an existing user the login fails ( tried the Windows Login and Standard ).  Do I have to add a group role for the entire domain?

I'm fairly new to DNN and could use some direction on this.  Thanks

Thank you for the suggestions. I quickly followed up on the first.  The event viewer showed the following every time I attempted to authenticate w/ a good account and pwd.  ( note I also tried w/  the domain prefix):

StackTrace:
Message: System.Runtime.InteropServices.COMException (0x8007052E): Logon failure: unknown user name or bad password. at System.DirectoryServices.DirectoryEntry.Bind(Boolean throwIfFail) at System.DirectoryServices.DirectoryEntry.Bind() at System.DirectoryServices.DirectoryEntry.get_NativeObject() at DotNetNuke.Authentication.ActiveDirectory.ADSI.ADSIProvider.IsAuthenticated(String Path, String UserName, String Password)
Source:

I followed up by trying all the applicable binding types secure, fastbind, and delagation.  Each time w/ the an error to the event log like above.  Anyone have ideas? 

I'm going to explore the impersonate next however that road is short and can not be used in our prod environment.

Henri,

That was it, thank you.  I had to login w/   <account>@<domain>  .  I was incorrectly under the impression that the 'email domain' would be appended to logins w/o a domain. Couple of questions for you?  Do know if this is documented anywhere besides the user guide? 

Thank you ,