[Thinlinc-technical] Export DISPLAY into Thinlinc session

[Mattias Molin]

Hi all!

I have searched through the documentation, all topics in the mailing 
list + searched the net for clues but I am not successful in finding 
what I want. I would appreciate some help to get me going in the right 
direction solving my problem.

*** In short:

I am having problems exporting DISPLAY from another machine into a start 
Thinlink session (using the official ThinLinc client).

*** Problem description:

In our solution we will run multiple servers hosting various kinds of 
software. These applications should be started locally but should be 
displayed within a ThinLinc Client session. In particular we will later 
use the HTML5 as the ThinLinc client but the HTML-client is not being 
used at the moment (until this problem is solved). For simplicity and to 
get some progress in solving the basic issues I am currently using 
xclock and xterm as example applications. These applications are not 
supposed to be used in the final solution - only for troubleshooting.

*** Host overview:

Guest1, with IP .91: This machine holds the binaries/applications. In 
this case currently xterm and xclock. This is where applications are 
started.
Guest2, with IP .92: This machine has Cendio installed and acts as 
Master/Agent. This is where applications should display. Xclock or xterm 
are NOT installed in this host.

Both Guest1 and B are currently running in VirtualBox with CentOS 6.5 
(limited) + Gnome desktop (hence all X deps exist) installed.

*** Basic test (that works):

I am logged into both hosts (Guest1 and Guest2) in a more "normal" 
manner - i.e. using the VirtualBox GUI.

* Guest2 (192.168.0.92):

[vagrant at guest2 ~ ]$ xhost +
access control disabled, clients can connect from any host
[vagrant at guest2 ~ ]$ env | grep DISPLAY
DISPLAY=:0.0

* Guest1 (192.168.0.91):

[vagrant at guest1 ~ ]$ export DISPLAY="192.168.0.92:0"
[vagrant at guest1 ~ ]$ xclock

This basic test works fine. Xclock is started on Guest1 and shows up on 
Guest2 as expected.

*** Extended test (that fails):

I am logged into Guest1 using the VirtualBox GUI while connected to 
Guest2 via the ThinLinc Client.

* Guest2 (192.168.0.92):

[vagrant at guest2 ~ ]$ xhost +
access control disabled, clients can connect from any host
[vagrant at guest2 ~ ]$ env | grep DISPLAY
DISPLAY=:1.0

* Guest1 (192.168.0.91):

[vagrant at guest1 ~ ]$ export DISPLAY="192.168.0.92:1"
[vagrant at guest1 ~ ]$ xclock
Error: Can't open display: 192.168.0.92:1
[vagrant at guest1 ~ ]$ export DISPLAY="192.168.0.92:1.0"
[vagrant at guest1 ~ ]$ xclock
Error: Can't open display: 192.168.0.92:1.0

This operation fails. I am sure I am missing the point somewhere or I 
need to do something with the Cendio server config. I just do not have a 
clue what to do to make this work. Any ideas? Any help or ideas are 
appreciated!

BR / Mattias