disable ssh root login

Install the ssh server and client.

ROOTPROMPT$ apt-get install openssh_client openssh_server

Then open the /etc/ssh/sshd_config file

ROOTPROMPT$ emacs /etc/ssh/sshd_config

and change the"PermitRootLogin" option to 'no'

...#SKIP to relevant section
# Authentication:
LoginGraceTime 120
PermitRootLogin no
StrictModes yes

More details at the ssh man page.