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VNC gives users a remote desktop Graphical User Interface.

Connection Mechanism

Our cpu1 server runs tigerVNC, this allows users to start server instances with a shell command vncserver. Users need a VNC viewer to connect to a VNC server instance.

UltraVNC connection showing a user desktop

Step 0: Configure password (First time only)

Connect via SSH and ensure you have setup a VNC password: vncpasswd. This should create the hidden folder ~/.vnc if it didn't already exist. Copy /home/utils/vncstuff/xstartup to ~/.vnc to get a working configuration for a desktop environment(xfce). This step may already have been done for you by an admin, in which case your vnc password equals your user name.

Step 1: Start a remote vncserver instance

A user must first start a running vnserver process and connect to it: vncserver will start an instance with default settings. You can see your running instances with vncserver -list.

A more specific example: vncserver -name <sessionname> :<N> where <N> is an integer. E.g. vncserver -name bobsvnc :23 will create a session at display number 23, which means they have to connect to port 5923. The port formula is 5900+N. Ports occupied by others are not available, so if 23 was taken in the previous example it would have tried 24, etc.

Step 2: Establish an SSH tunnel

SSH port forwarding is the canonical solution in case the firewalls prevent direct connection to the vncserver:port. See shell access for details. The current firewalls do not allow direct access on the VNC ports, so this step is necessary.

If you've ever use X forwarding before, that's the same concept.

Step 3: Connect with your VNC viewer

  • Open the viewer and connect to localhost:<port>, where <port> depends on your tunnel configuration. E.g. You setup a vncserver on 5908, then with a tunnel mapping port 5900 to remote:5908, your VNC viewer would connect to localhost:5900. You'll be prompted for your vnc password to continue.
To minimize bandwidth and cpu usage, do not use too many sessions, kill redundant sessions with vncserver -kill, and don't use uncompressed high quality video settings

In case the remote desktop reports errors upon first (successful) login, this seems to be a bug related to xfce and/or anaconda. Try deactivating conda default environment or modifying your PATH variable.