The default sshd configuration on SuperCluster seems to have changed to a more secure setup, which is great in a production type environment but sucks in my gung-ho lab environment.
The things I like to re-enable in my /etc/ssh/sshd_config are
X11Forwarding yes KeepAlive yes ClientAliveInterval 30 ClientAliveCountMax 99999
Then I stop and restart sshd and my life becomes a lot easier.
#svcadm restart ssh