Access control enhancements, network access unit and service provider server for delivery of video and other services

A method of providing secure multicast over a local access network by means of a network access unit having a channel request vetting function and a permitted channel list. Channel requests from a subscriber are vetted with respect to the permitted channel list and forwarded only if permitted. The permitted list may be dynamically updated under headend control to allow users to subscribe to, and unsubscribe from, services upon request.