====== VNC over SSH ======

For security, all VNC connections must use [[wp>Tunneling_protocol#Secure_shell_tunneling|ssh tunnels]]. 

  * The {{csovnc.pl}} script is the recommended method of connecting to the VNC desktops. It works on Mac OSX and linux systems. 

  * Download the {{csovnc.pl}} script to a convenient location. Make it executable: \\ ''mycomp> **chmod 755 csovnc.pl** ''
  * The script sets up the ssh tunnel and opens the VNC viewer: \\ ''mycomp> **csovnc.pl -C -l //user// //function// **''
  * The script recognizes either function names or port numbers. For example, to connect to the UIP desktop: \\ ''mycomp> **csovnc.pl -C -l //user// uip **''
  * Choose the desktop //function// from this [[remoteobs#vnc_desktops|table]].
  * Some instruments use more than one desktop; run the script again if necessary.
  * On linux, the script tries the ''vncviewer'', ''krdc'', and ''vinagre'' viewers, in that order. To change the order, i. e., to try ''krdc'' before ''vncviewer'', use ''-v'': \\ ''mycomp> **csovnc.pl -C -v //viewer// -l //user// //function// **''

  * It is also possible to run the viewer on kilauea with an X window display on your local computer. This is also appropriate if you are at the telescope. \\ ''mycomp> **ssh -C -X //user//@kilauea.caltech.edu **'' \\ '' kilauea> **csovnc.pl //function//**''


==== Manual configuration ====

  * If the {{csovnc.pl}} script fails for some reason, manual configuration may be necessary. 
  * In these instructions, //N// is the VNC desktop number and 59//NN// is the VNC port. Desktop 1 corresponds to port 5901, etc.
  * Choose the desktop //function// and corresponding port number from this [[remoteobs#vnc_desktops|table]]. 
  * To connect to more than one virtual desktop simultaneously, change the intermediate port number, 12345 → 12346, etc., for the subsequent connections.

=== Mac OSX ===

  * Either download and use the [[http://hea-www.harvard.edu/~fine/OSX/tunnelopen.html|tunnelopen.pl]] script, \\ ''mac> **tunnelopen.pl -C -l //user// vnc:%%//%%kilauea.caltech.edu:59//NN//**''
  * Or setup the tunnel and screen sharing (vnc viewer) manually. You'll need two terminal windows:\\ ''mac1> **ssh -C -L 12345:localhost:59//NN// //user//@kilauea.caltech.edu**''\\ ''mac2> **open vnc:%%//%%localhost:12345**''

=== Linux ===

  * Either use ''vncviewer'' with the ''via'' option,\\ ''linux> **vncviewer -shared -via //user//@kilauea.caltech.edu ://N//**''
    * Not all versions of ''vncviewer'' support the ''via'' option. 
    * With this method, enabling ssh compression is complicated.
  * Or setup the tunnel and VNC viewer manually. You'll need two terminal windows:\\ ''linux1> **ssh -C -L 12345:localhost:59//NN// //user//@kilauea.caltech.edu**'' \\ ''linux2> **vncviewer -shared localhost::12345**'' 

=== X display ===

  * It is also possible to run the VNC viewer on kilauea with an X window display on your local computer. This is also appropriate if you are at the telescope.  \\ ''mycomp> **ssh -C -X //user//@kilauea.caltech.edu ** '' \\ '' kilauea> **vncviewer -shared  localhost://N//**''

=== Windows ===
  * [[windows_vnc]] does work but has not been extensively tested.