Hi,
If I understand correctly, AD Authentication Provider is best fit for an organization with a windows domain, users who login to their computers and want to open the dotnetnuke portal and magically be logged in, and see their personalized content.

Here's what I need, though, so please tell me if this is easy to do or not...

My portal will be for a set of users from over 100 different agencies.  Each may or may not have their own domains.  But users from all these agencies already have an ID/PW in my Active Directory, because they use a custom (non web based) application and their id/pw is stored in AD and accessed / updated via LDAP functionality.  Now I want to create a portal for their use.  Because their computers are not part of my domain, I don't need "integrated" windows security.  But I want to prompt them for an ID/PW, and I want to authenticate the ID/PW they entered against my Active Directory.  What I really need is an "LDAP Authentication Provider".  No integration with Windows Security on the client is desired.  I would want that feature completely disabled, because not a single user of my website will actually be logged onto the AD domain I wish to authenticate with.

Will the AD Authentication Provider work this way?  Can anyone point out the best way to achieve this?

Thanks in advance for any advice/insight you can provide.

Thanks a lot for this, it is very encouraging.  And I would certainly want to eliminate the need to enter the domain name on login, I'm surprised it is not a configuration parameter for the plug in to specify the default domain... 

When you say "use a script on the login.ascx" do you mean edit the login.ascx to prefix the domain name before calling the authentication algorithm?

Thanks again.