On Tue, 5 May 2009, William Shu wrote:

> Dear All,
> I think I now have a clearer approach to finding solutions to some of my problems. the suggestions of Stephen, Troy and Miles were particularly helpful.
>
> First, the the solutions obtained so far:
> enabling Xforwarding and restarting daemons (e.g., sshd) permits me to have trouble-free displays over ssh or from xterm windows of different users on the same console.
>
> From the help offered, I think my solution strategy for multi-terminal display could be one of the following:
>
> 1) Bring up vnc display, have a "master vnc viewer" that can read/write
>    on the display, and let all the other vnc viewers be "slave vnc
>    viewers" that can only view the display. Unfortunately, blocking
>    keyboard/mouse actions using the options menu from pressing the F8
>    key can be reset by the user. An suggestions to configure vnc to have
>    such master-slave viewers?

How about something like this from the clients:

   vncviewer -via gateway-host -Shared -viewonly -MenuKey 'NoSuchKey' serverhost:0

In tests here that seems to disable the keyboard input and prevents use of 
the F8 menu... (well assuming that you don't have a 'NosuchKey' keysym 
available)...  Also:

   vncviewer -via gateway-host -Shared -viewonly -MenuKey '' serverhost:0

appears to do much the same.  Of course if they can connect to the 
vnc-server then they could launch a different vncviewer without those 
options, but depending on how malicious your users are this may be 
acceptable... :-)

(I'm assuming that you want to use -via xxx to do the ssh tunnelling 
stuff)...

> 2) Create a separate account, which can possibly become insecure by
>    granting xauth authorities, and use vnc to display whatever. While
>    the implications of extending access (via xauth) frighten, the use of
>    a video conferencing tool, such as EVO, seem to require internet
>    access, whereas the machines I'll use are in a closed LAN. Does
>    anyone know of a video conferencing tool that does not register
>    to/through the internet?
>
> Once more thank you all for the support.

  -- Jon