We were configuring OpenStack on a private 192.168 network and needed to use a web browser to browse to the OpenStack dashboard.
The quickest easiest way to do that is by:
ssh -D 8888 jonny@sshgateway
From the ssh manpage:
-D Specifies a local “dynamic” application-level port forwarding. This works by allocating a socket to listen to port on the local side. Whenever a connection is made to this port, the connection is forwarded over the secure channel, and the application protocol is then used to determine where to connect to from the remote machine. Currently the SOCKS4 and SOCKS5 protocols are supported, and ssh will act as a SOCKS server.
Then set Firefox to use a Socks proxy of the address localhost:8888 and browse to the address of the machine on the internal private network.
Another alternative is to use Squid on the gateway to proxy http to the private internal addresses.