1) The following settings in `/etc/sshd_config' allow Marionnet to connect 
   or send commands to virtual machines:

   PermitRootLogin yes
   StrictModes no
   PubkeyAuthentication yes

2) The private key `id_rsa_marionnet' should be used by Marionnet in a command like
   the following:
   ssh -i id_rsa_marionnet -o PreferredAuthentications=publickey root@172.23.0.1 ls /

3) The public key `id_rsa_marionnet.pub' should be appended to .ssh/authorized_keys 
   for both "root" and "student" accounts into the virtual machines.
