SSH and clusters

[Philip Juels]

Sometimes my users simply want to run a batch process on any given node
within our cluster as opposed to true parallel processing.  So they use
ssh to access the master node of our cluster and then rlogin or telnet
to access the clients from the master (the client nodes are on an
isolated intranet with the master acting as gatekeeper).  Is this
insecure?  Should we run ssh for connections withing the cluster?  My
understanding of ssh is that it's like a secure pipe...anything on top
of it should be encrypted.

Thanks,

Philip Juels
philip_juels@harvard.edu