So I have just rolled over my Untangle box to RADIUS authentication instead of active directory authentication. However, what I've found out is that if I disable AD Authenticaiton and have RADIUS connected my logon script is still working and giving authentication to a specific username. When the AD Connector is disabled the following URL should not grant access.
adpb/registration?username="+strUser+"&domain="+strDomain+"&hostname="+strHostname+"&action=login"