Ssh Port forwarding

SSH port-forwarding can allow secure access to remotehost/remoteport even if firewalls don't allow a direct connection; as long as we can access an ssh-server that has access to the remotehost/remoteport.

ssh -f -L localport:remotehost:remoteport hostname tail -f /dev/null

ssh-server must be running on hostname and hostname must be able to connect to remoteport and remotehost.