D.4 Tunneling with OpenSSH

The -L localPort:remoteHost:remotePort option to ssh is used to setup tunnels. The following are examples of some tunneling arrangements that might be useful in a CCA context:

• Establishing an SSH connection to the head node of a cluster which will forward SSH connections to an internal node. Then using the tunnel to make a direct connection to the internal node:

  $	ssh -L 2022:clusterInternalNode:22 clusterHeadNode

  $	ssh -p 2022 localhost

• Establishing an SSH connection to a firewalled machine which will forward connections from the Ccaffeine GUI running locally to the Ccaffeine framework backend running remotely:

  $	ssh -L 3314:remoteHost:3314 remoteHost

  $	simple-gui.sh -port 3314 -host localhost

• Establishing tunnels to an internal node of a cluster for both SSH and Ccaffeine GUI connections:

  $	ssh -L 2022:clusterInternalNode:22 \ -L 3314:clusterInternalNode:3314 clusterHeadNode

which can be used precisely as in the preceeding examples.