Hi, Richard. You add more base DNs if you want oxAuth to consider those locations when it verifies credentials of an user attempting to log in as well (for example, in your AD domain there are several OUs, and users you need are distribute over all of them; so you add them all as base DNs there). So in such case oxAuth will first search under base_DN1, then under base_DN2 and so on - until it will find first user with key attribute matching the one that was submitted by user as "Username" at web UI's login form. Natrually, if you use Cache Refresh as well (what is normally the case), you need to add those extra base DNs to its configuration as well.

I'm not even 100% sure which screen you are asking about. It might be helpful if you uploaded the screenshot somewhere and provided a link to it.

Bigs thanks ........great service as always.