freenx
location of client key: /var/lib/nxserver/nxhome/.ssh/client.id_dsa.key

clients can be found at: www.nomachine.com
client key must be imported into client config for authentication

some useful nxserver commands:
nxserver --help
nxserver --adduser <user>
nxserver --passwd <user>
nxserver --deluser <user>
nxserver --restart
nxserver --stop
nxserver --start
nxserver --status
nxserver --list (lists running sessions)
nxserver --listuser (lists enabled users)
nxserver --broadcast <message> (send msg to all users)
nxserver --cleanup (terminates all running sessions)