Systems, methodologies, media, and other embodiments associated with provisioning an Internet Protocol (IP) core network services multimedia subsystem (IMS) are described. One exemplary system embodiment includes a Home Subscriber Server (HSS) logic operably connectable to components including, a user database, an application server (AS), and a permissions database. The HSS logic may be a component of an IMS that facilitates communications between application servers and users. Thus, the HSS logic may be configured to receive an AS-to-user-database-interface-message (AUDIM) and to selectively update the permissions database based, at least in part, on the AUDIM. The user database may store user data concerning IMS users and the permissions database may store information for controlling AUDIM initiated interactions between an AS and the user database.