Subject: XDMCP termial on a vserver: DISPLAY is set to a certain running vserver
From: Ekkard Gerlach <ekkardgerlach@aiai.de>
Date: Sun, 27 Nov 2011 00:17:03 +0100

Hello, 

DISPLAY variable is set to a certain running vserver when XDMCP is started 
on a vserver host by 

     host:#~/usr/bin/X :1 vt08 -query 192.168.0.100. 

And not to host. Stopping this certain vserver an DISPLAY variable is
set correctly to "host.local". Why?

Background: The vserver in one of my customers office is also used as 
XDMCP-Terminal (why not?). The XDMCP-Server is a Suse 11.1 machine.
And it works fine. Now I want to start x11vnc on the vserver to make 
montoring for support affairs. Using /etc/X11/xdm/Xsetup on the Suse 
11.1 XDMCP-Server I inplace the code: 

    [...]
    lhost="${DISPLAY/:*/}"
    host="${lhost/.*/}" 
    echo lhost: $lhost  "   host:" $host > /tmp/x11vnc_host
    [...]
 
because I want to know "where does the Client come from" to start x11vnc 
on that remote machine, in my case her its the vserver. If there is
the vserver "cups" running von the vserver the I get 

    lhost="cups.local" 
    host=cups

When shutdown vserver cups:  vserver cups stop   then I get the right 
DISPLAY: 
    lhost="host.local"
    host=host

Why? 

BTW "host" ist not the real name of the vserver, I changed it for better 
understanding. 

I've three vservers runing: 
root@<host>:~# vserver-stat
CTX   PROC    VSZ    RSS  userTIME   sysTIME    UPTIME NAME
91       5 140.1M   3.8M   0m00s95   0m00s62   6d00h17 misc
92       6   226M   7.5M   0m00s11   0m00s84  25m31s32 cups  ->   IP 0.92
93       8 384.2M  10.3M   0m00s40   0m00s48  17m14s94 samba ->   IP 0.93

Stopping and starting vserver samba  does NOT make samba to the favorite vserver
which DISPLAY variable is sent, its only vserver "cups"! Why is cups the 
favorite machine on the vserver?

<host>:~# cat /etc/hosts
[...]
192.168.0.100   suse111.local suse111
192.168.0.91   misc.local  misc
192.168.0.92   cups.local  cups

<host>:~# /etc/ssh/sshd_config
[...]
#ListenAddress 0.0.0.0
ListenAddress 192.168.0.2    <- thats IP of host vserver 
Protocol 2
[...]

tia
Ekkard