
Here you can define the rights for domain administrators. The options are self-explanatory. By default, you can assign the rights to manage particular type of accounts. If you check it only in the dialog, it means this domain administrator will have rights to manage such accounts only in the domain it belongs to. If you want to assign this domain administrator also rights for different domains, you have to use the domain.dat file click the Advanced button to edit the file.
In that file, you can assign rights not only for type of accounts and additional domains but you can also exactly define which domain options can the domain administrator edit/change/see. See the example file for exact syntax.
This domain administrator is also prevented from accessing users mailboxes and read their messages, but can access spam queues.