A system is provided to deliver an application, hosted by a private application provider system, over a network to a user device, comprising: an application delivery system that includes a first network interface, a network security interface and a second network interface; wherein the network security interface is configured to determine whether a user or device request for access to an application is valid, and in response to determining that the user or device request for access to the first application is valid, to send the user or device request to the application agent.