SSH Tunneling [Port Forwarding] - this is also a technic called "Port Forwarding". The simply "Tunneling" is mean is send data through other connections that have been establised.
The protocol of "Tunneling" is SSH and SSL, SSH is one that which we discussed. SSH is the protocol which can be used for wrap the data in the protocol, the protocol is not only HTTP. SSH was designed as a replacement a TELNET and SHELL. Because the encryption which to use of SSH was provide confidentiality and integrity of data network. Below is a illustration of SSH Tunneling.
in the picture above, his illustration is SSH tunneling used for Port Forwarding or you can called "proxy". PC Client will access a SERVER HOST and than from SERVER HOST giving PORT FORWARDING to used for Listen Port on Client PC.
For example, Client PC having IP 184.108.40.206 and IP SERVER HOST is 220.127.116.11, and than Client will access URL www.google.com using SSH Tunneling, so the information IP who accessing on www.google.com is SERVER HOST IP is 18.104.22.168. In the other words, accessing internet using SSH Tunneling is safe.
Paper 4Share - SSH Tunneling [Port Forwarding]