Can't connect to X11 window server

I am new to linux(using Suse 9.3) and have a program (grahics) on running it I get this error
Exception in thread "main" java.lang.InternalError: Can't connect to X11 window server using ':0.0' as the value of the DISPLAY variable.
at sun.awt.X11GraphicsEnvironment.initDisplay(Native Method)
at sun.awt.X11GraphicsEnvironment.<clinit>(X11GraphicsEnvironment.java:134)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:141)
at java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsEnvironment.java:62)
at java.awt.Window.init(Window.java:231)
at java.awt.Window.<init>(Window.java:275)
at java.awt.Frame.<init>(Frame.java:401)
at javax.swing.JFrame.<init>(JFrame.java:198)
at JPanels.<init>(JPanels.java:15)
at JPanels.main(JPanels.java:11)
On the linux machine, it runs fine, but when I ssh into the box and try to run it I get this error. Y is this so an any solution.

X server usually isn't configured to run remotely because it runs as root. You can use NFS to link to the executables and libraries, and then run the program on another X server. Lastly, you can configure the X server to run on a remote machine. This is a big security hole. You might also want to to try logging into ssh as a regular user on the remote machine and:

xhost +

Then log in as root and try to run it again.

But how do I use NFS and besides what is NFS, sorry I am new. Please could you give me step by step to tackle this problem.
Thank.

Originally Posted by kofibull I am new to linux(using Suse 9.3) and have a program (grahics) on running it I get this error Exception in thread "main" java.lang.InternalError: Can't connect to X11 window server using ':0.0' as the value of the DISPLAY variable. at sun.awt.X11GraphicsEnvironment.initDisplay(Native Method) at sun.awt.X11GraphicsEnvironment.<clinit>(X11GraphicsEnvironment.java:134) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:141) at java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsEnvironment.java:62) at java.awt.Window.init(Window.java:231) at java.awt.Window.<init>(Window.java:275) at java.awt.Frame.<init>(Frame.java:401) at javax.swing.JFrame.<init>(JFrame.java:198) at JPanels.<init>(JPanels.java:15) at JPanels.main(JPanels.java:11) On the linux machine, it runs fine, but when I ssh into the box and try to run it I get this error. Y is this so an any solution.

add the -Y flag when you SSH to use X forwarding

ssh -Y user@host ...

Thanks,

I did the xhost +myLinusBox.com and that added new access list. But it did not do anything. Sorry, but I am able to run my JPanel.class on the Linux Box but not when I am away from home. I get the
"Can't connect to X11 window server using ':0.0' as the value of the DISPLAY variable."
I have tried compiling as root and regular user but no luck. I am still lost.

Thanks in advance

Originally Posted by kofibull Thanks, I did the xhost +myLinusBox.com and that added new access list. But it did not do anything. Sorry, but I am able to run my JPanel.class on the Linux Box but not when I am away from home. I get the "Can't connect to X11 window server using ':0.0' as the value of the DISPLAY variable." I have tried compiling as root and regular user but no luck. I am still lost. Thanks in advance

Did you read my post above?

I read the post and did the ssh - Y ssh -Y user@host but no luck

I am not clear on your original post but I believe you are logging in to a remote machine to run an x-windows application that will display on your local terminal. If this is the case there are a few things that need to be done.

On the local machine allow remote access to your loacl x-windows.
Change your x configuration files to allow remote access.
This will depend on what version of X you are using.

Two examples
Older RH distros (xfree, early x.org)
in /etc/X11/gdm/gdm.conf
DisallowTCP=false

Newer RH distros (newer x.org)
in /etc/gdm/custom.conf
[security]
DisallowTCP=false
[xdmcp]
Enable=true

Restart x-windows.

Alloy a specific remote machine to access to your local x-windows
On your local machine: xhost +(remote machine)

Telnet,ssh or whatever into remote machine
export Display=local_machine:0.0
run application on remote machine


There are more secure ways to to this as a previous post implies. I do this way everyday on a relatively secure network without worries.

Hello,
Thanks for reading and replying,
I do not have the gdm folder in my filesystem but these are the files in etc/X11/
". qt_gtk_fnt2fntrc xdm Xmodmap.remote
.. qt_plugins_3.3rc XF86Config xorg.conf
fs .qt_plugins_3.3rc.lock XF86Config-20060506 xorg.conf.install
fvwm2 qtrc xim xorg.conf.saxsave
kstylerc .qtrc.lock xim.d Xresources
.kstylerc.lock rstart xinit xserver
lbxproxy twm xkb xsm
proxymngr WindowMaker Xmodmap
"
do you know where elseI might have to look or prop installing the folder?

This is the senerio, lest say I have a program that I am running but I would run it on your server. If I try doing so it gives me the error as stated above.
I am using suse 9.3

Thanks

Ko

A quick google search for suse allow remote x clients provided this information from the first hit.

/etc/sysconfig/displaymanager
# Allow remote access to your display manager (kdm only for now)
#
DISPLAYMANAGER_REMOTE_ACCESS="yes"

Also the export Display=... should be export DISPLAY=... (all caps)

Thanks,
I have the "DISPLAYMANAGER_REMOTE_ACCESS="yes"" already but no luck.