[KLUG Members] can't open display for remote X app

[bfdamkoehler at worldnet.att.net]

The reason why a Suse 9.3 X server won't allow remote X access is that 
its turned off by default. Turn it on as described below by altering the 
setting for DISPLAYMANAGER_XSERVER_TCP_PORT_6000_OPEN and then you 
probably have to at least log in again and maybe reboot. This allows the 
X server to listen for network connections from other machines, and it 
is ONLY for Suse. 

The only RHE that I have run is RHE3 and it does not have this issue, 
but its pretty darn old. I assume that your RHE is 4. Is this true? Does 
it use an xorg xserver or an xfree86 x server? One way to tell is the 
run the command "ls -l /etc/X11/X".  This file is a symbolic link to the 
X server that you are using, and it should be something like 
"../../usr/X11R6/bin/XFree86*" or "../../usr/X11R6/bin/Xorg*".




John Pesce wrote:

>Yes please. I've never used an HPUX box before. I would love the URL of
>the pre-built .depot packages. Even better, is there a mini howto to
>install them?
>
>However, I would still like to understand why my RH and Suse boxes won't
>allow remote X displays with using ssh. Is there a new X config that
>disables xhost + ?
>
>
>On Sun, 2005-12-18 at 12:39 -0500, Bruce Smith wrote:
>  
>
>>I also run a mixed Linux & HPUX environment.  My solution was to install
>>SSH on all of my HPUX boxes.  It's very easy if you use one of the
>>pre-built .depot packages (HPUX equivalent of RPM).
>>
>>Let me know if you need the URL of the .depot repositories.
>>
>> - BS
>>
>>
>>    
>>
>>>I too have had issues lately. There are two issues that I am aware of.  
>>>First, by default Suse configures X so that only the local machine can 
>>>use it. This is easy to fix but probably won't fix your problem because 
>>>of the second issue. The second issue I am less clear about, and it  
>>>involves differences in behavior between xfree86 X which was used by the 
>>>older distributions and the xorg X which is currently being used.
>>>
>>>To turn on remote X support in Suse you can either use the /etc/sysconf 
>>>editor in yast or directly edit /etc/sysconfig/displaymanager and change 
>>>DISPLAYMANAGER_XSEREVER_TCP_PORT_6000_OPEN from "no" to "yes" (you may 
>>>or may not want to alter DISPLAYMANAGER_ROOT_LOGIN_REMOTE  as well).
>>>
>>>With xfree86 "xhost +" would fix any problems, and you could always 
>>>specify "DISPLAY=somenode:0" and it would work. If the X server that you 
>>>are displaying on is running xorg you must use a "DISPLAY=localhost:nn" 
>>>type of setting, which requires the use of ssh. If you really want to 
>>>continue to launch X sessions from a telnet session then maybe you 
>>>should investigate xauth (not that I have).  Finally, using an xorg X 
>>>server you can't su from one account to another (on the remote machine) 
>>>and expect your remote X to work with it. I occasionally have problems 
>>>even if I make sure that I have everything as described above. Creating 
>>>another session typically fixes it.
>>>
>>>
>>>
>>>John Pesce wrote:
>>>
>>>      
>>>
>>>>Remote X display over ssh works fine. 
>>>>
>>>>I can't remote display anymore when I rsh or telnet.
>>>>
>>>>
>>>>On Sat, 2005-12-17 at 10:22 -0500, Stuart Gillis wrote:
>>>> 
>>>>
>>>>        
>>>>
>>>>>On your Suse box, edit /etc/ssh/ssh_config
>>>>>
>>>>>Change :
>>>>>
>>>>>#   ForwardX11 no
>>>>>   to
>>>>>ForwardX11 yes
>>>>>
>>>>>That should fix it.
>>>>>
>>>>>Stu
>>>>>
>>>>>
>>>>>On 12/15/05, John Pesce <pescej at sprl.db.erau.edu> wrote:
>>>>>   
>>>>>
>>>>>          
>>>>>
>>>>>>Hi,
>>>>>>
>>>>>>I've encountered a wierd and unexpected X error. I guess I've been ssh
>>>>>>-X tunneling for so long I didn't notice until now.
>>>>>>
>>>>>>My older workstations that still run RH9 work as expected. I can xhost
>>>>>>nextbox, telnet or rsh from it into nextbox, set my DISPLAY to other:0,
>>>>>>and run xeyes.
>>>>>>
>>>>>>All my other newer boxes are running Suse 9.3 or RHE have ssh and not
>>>>>>telnet or rsh. We just got a new HP unix box installed for a special
>>>>>>purpose app and it does not have ssh.
>>>>>>On my RHE box I xhost +, and then telnet to the HP, setenv DISPLAY
>>>>>>RHE:0.0 and try and run the app.
>>>>>>I get Error: Can't open display: RHEIP:0
>>>>>>
>>>>>>I thought this was strange so I went to a Suse 9.3 box and tried to do
>>>>>>the same thing with the same error. Then I tried running xeyes on the
>>>>>>Suse 9.3 box and displaying it on another Suse 9.3 box, same error.
>>>>>>
>>>>>>I don't have workstation firewalls. What gives?
>>>>>>Did X add some new feature to disable xhost +?
>>>>>>
>>>>>>I can xhost + on the older RH9 box and telnet to the HP and remote
>>>>>>display ok.
>>>>>>            
>>>>>>
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