SSH tunneling heißt ssh Verbindung mit einem entfernten Rechner aufzubauen, wobei man den Port für Empfang bei sich bestimmt.
http://superuser.com/questions/96489/ssh-tunnel-via-multiple-hops
You basically have three possibilities:
Tunnel from localhost to host1:
ssh -L 9999:host2:1234 -N host1
As noted above, the connection from host1 to host2 will not be secured.
Tunnel from localhost to host1 and from host1 to host2:
ssh -L 9999:localhost:9999 host1 ssh -L 9999:localhost:1234 -N host2
This will open a tunnel from localhost to host1 and another tunnel from host1 to host2. However the port 9999 to host2:1234 can be used by anyone on host1. This may or may not be a problem.
Tunnel from localhost to host1 and from localhost to host2:
ssh -L 9998:host2:22 -N host1
ssh -L 9999:localhost:1234 -N -p 9998 localhost
This will open a tunnel from localhost to host1 through which the SSH service on host2 can be used. Then a second tunnel is opened from localhost to host2 through the first tunnel.
Proxy