US Patent 7359978 Providing secure access through network firewalls

To enable controlled, secure connections using a versatile protocol such as TCP/IP to be established through a firewall and proxy server, the versatile protocol is tunnelled using HTTP. Client to server communications are effected using an HTTP POST operation. Server to client communications are effected using an HTTP GET operation to establish a tunnelled socket; this socket is closed within an interval less than any timeout imposed by the proxy server and immediately re-established by another GET operation, irrespective of whether data continue to be pending for communication to the client. A globally-unique ID is included in each POST and GET message to enable related messages to be recognized.