Install Nomachine NX Server Free Edition on Debian Linux

The Nomachine nxserver free edition has limitation: allows only 2 concurrent user sessions. But it is fine for me to connect to my Linux workstation at work. It is easier to setup than the freenx server. See the guide below:

1. Run the following commands to download and install nomachine nxclient, nxnode and nxserver packages:

   if [[ $(uname -m)=="x86_64" ]]; then export MARC=amd64; else export MARC=i386; fi
   wget http://web04.nomachine.com/download/3.5.0/Linux/nxclient_3.5.0-7_${MARC}.deb
   sudo dpkg -i nxclient_3.5.0-7_${MARC}.deb
   wget http://web04.nomachine.com/download/3.5.0/Linux/nxnode_3.5.0-9_${MARC}.deb
   sudo dpkg -i nxnode_3.5.0-9_${MARC}.deb
   wget http://web04.nomachine.com/download/3.5.0/Linux/FE/nxserver_3.5.0-11_${MARC}.deb
   sudo dpkg -i nxserver_3.5.0-11_${MARC}.deb
   

2. Setup your own server private key instead of the nomachine key:

   sudo ssh-keygen -t dsa -f /usr/NX/home/nx/.ssh/id_dsa
   sudo chown nx:nx /usr/NX/home/nx/.ssh/id_dsa
   sudo mv /usr/NX/home/nx/.ssh/authorized_keys2 /usr/NX/home/nx/.ssh/authorized_keys2.old
   sudo cat /usr/NX/home/nx/.ssh/id_dsa.pub >> /usr/NX/home/nx/.ssh/authorized_keys2
   

   You can now use the private key in /usr/NX/home/nx/.ssh/id_dsa for your client to connect to the nxserver.
3. Secure ssh for NX server by editting /etc/ssh/sshd_config as root:
   • Enable PubkeyAuthentication for all:

     PubkeyAuthentication yes

   • Disable PasswordAuthentication for all:

     PasswordAuthentication no

   • Allows PasswordAuthentication only for the FreeNX users by appending the following line to sshd_config:

     Match Group nxusers 
         PasswordAuthentication yes

     or if you want to allow individual users:

     Match User john alex
         PasswordAuthentication yes