The present invention is directed to a method of call rejection provided for use in connection with a data network. It includes establishing a point-of-presence which serves as a termination point for receiving calls from clients. Received calls are then multiplexed into a tunnel as separate identifiable tunnel sessions. The tunnel sessions are received at a network server of the data network. Next, it is determined for each tunnel session if access to the data network is to be denied. If access is denied, then a call rejection message is returned to the point-of-presence via the tunnel. In a preferred embodiment, the call rejection message identifies the tunnel session which is denied access and a reason for denial such that at the point-of-presence appropriate action may be taken in response thereto. In the case of suspected intrusion by an unauthorized entity, this action involves a form of deterrent and/or surveillance. In the case of internet telephony, where the data network cannot successfully handle the call, the action involves rerouting the call via a crank back.