Using VNC to shadow clients

From K12LTSP Wiki

Odin Nosen posted these instructions to the K12LTSP mailing list for using VNC to shadow clients, that is, to allow person at the console to see what is displaying on a client. Hopefully, this ability will be incorporated into fl_teachertool someday, but for now (January, 2006) it runs separately.

<verbatim> This is how we enable remote control of the ltsp-clients:

Login at the terminalserver as root. Edit /opt/ltsp/i386/etc/lts.conf and add:

X4MODULE02 = vnc

Then edit the file /opt/ltsp/i386/etc/buildx4cfg and add the following under 'Section "Screen"' (but over 'EndSubSection'), so it looks like this:

Section "Screen"
      Identifier "Screen0"
      Device "My Video Card"
      Monitor "My Monitor"
      DefaultDepth  ${XCOLORDEPTH:-16}
      Subsection "Display"
              Depth ${XCOLORDEPTH:-16}
              Modes ${MODE*}
              Option "httpdir" "/usr/share/vnc/classes"
              Option "PasswordFile" "/root/.vnc/passwd"
              Option "rfbport" "5900"
              Option "usevnc"
      EndSubSection
EndSection

Now you'll have to make a password for the vnc-session. Run this command:

root@ts01 ~$ /usr/bin/vncpasswd

Choose a password and copy the password file into the ltsp-tree

root@ts01 ~$ cp -R -p /root/.vnc /opt/ltsp/i386/root/

Now you must copy the vnc-module and some libraries into the ltsp-tree:

root@ts01 ~$ cp /usr/X11R6/lib/modules/extensions/vnc.so /opt/ltsp/i386/usr/X11R6/lib/modules/extensions/
root@ts01 ~$ cp /usr/lib/libstdc  .so.6 /opt/ltsp/i386/usr/lib/
root@ts01 ~$ cp /lib/libgcc_s.so.1 /opt/ltsp/i386/lib/

I am told that you should make this link also, I am not sure if its necessary, but we'll do it:

root@ts01 ~$ ln -s /lib/libgccs.so.1backup /opt/ltsp/i386/lib/libgcc_s.so -f

Reboot the ltsp-client and use 'vncviewer' with ip og hostname to shadow the client.

Good luck... works like a charm. It may not be most secure way of doing it. But it's fast and it works. </verbatim>