Functionality of Secure Shell (continued)

Port forwarding
Port forwarding is a powerful tool that can provide security to TCP/IP applications including e-mail, sales and customer contact databases, and in-house applications. Port forwarding, sometimes referred to as tunneling, allows data from normally unsecured TCP/IP applications to be secured. After port forwarding has been set up, Secure Shell reroutes traffic from a program (usually a client) and sends it across the encrypted tunnel, then delivers it to a program on the other side (usually a server). Multiple applications can transmit data over a single multiplexed channel, eliminating the need to open additional vulnerable ports on a firewall or router.

For some applications, a secure remote command shell isn't sufficient and graphical remote control is necessary. Secure Shell's port forwarding capabilities can be used to create an encrypted tunnel over which an application can be run. Virtual Network Client (VNC), a cross-platform GUI remote control application, is a good example.

Port forwarding allows multiple TCP/IP applications to share a single secure connection