Abstract: A tunneling infrastructure provides TCP port forwarding from a client running on a client network to a server running on a server network, where the client and servers can be behind separate firewalls. To tunnel TCP, a “server socket” capability is provided, allowing the client to establish a connection to the server across the tunnel. A direct, port forwarding scheme is implemented. The client side is the driver for the tunnel operation. The client maintains multiple URL (Universal Resource Locator) connections to the server side tunnel allowing data to flow in both directions. The client's SendToServer connection(s) use the HTTP POST method to send data from the client side to the server side. The client's ReceiveFromServer connection(s) use the HTTP GET method, and allow data to be sent from the server side to the client side.

Abstract: A lightweight secure tunneling protocol or LSTP permits communicating across one or more firewalls by using a middle server or proxy. Three proxies are used to establish an end-to-end connection that navigates through the firewalls. In a typical configuration, a server is behind a first firewall and a client behind a second firewall are interconnected by an untrusted network (e.g., the Internet) between the firewalls. A first inside firewall SOCKS-aware server-side end proxy connects to the server inside the first firewall. A second inside firewall SOCKS-aware client-side end proxy is connected to by the client inside the second firewall. Both server-side and client-side end proxies can address a third proxy (called a middle proxy) outside the two firewalls. The middle proxy is usually started first, as the other two end proxies (server and client) will initiate the connection to the middle proxy some time after they are started.