[SOLVED ] Problem with forwarding X

[Pedzel]

Hi All.

I have a little problem that probably is easy to solve but i can not figure it out.

Previously i had a testing machine with X11 configured and i was connecting the machine via putty. Everything was working fine. After putting the machine into production without any graphical interface installed the problem occured. I think i have something wrong with putty configuration or ssh configuration. When i ssh to the server i try to launch any graphcal application (virt-manager for example), i got this:

Traceback (most recent call last):
File "/usr/share/virt-manager/virt-manager.py", line 376, in ?
_show_startup_error(str(run_e), "".join(traceback.format_exc()))
File "/usr/share/virt-manager/virt-manager.py", line 52, in _show_startup_error
import gtk
File "/usr/lib64/python2.4/site-packages/gtk-2.0/gtk/__init__.py", line 76, in ?
_init()
File "/usr/lib64/python2.4/site-packages/gtk-2.0/gtk/__init__.py", line 64, in _init
_gtk.init_check()
RuntimeError: could not open display

I did not have this problem before putting the server into production.
I suspect that this is caused by login procedure. It has changed sience putting it into production. Previously i had straight root login via ssh. Now i have to login with my normal account after that i am able to su into root. Could you point me what i have to change (or redirect the display variable) to get this X11 forwarding work via putty?


Thank You

[TrevorH]

Assuming that you have your ssh forwarding set up correctly, you will need to have the package xorg-x11-xauth installed on the server to use X. You probably need to run virt-manager as your own userid - it should prompt for the root password when you do so. Once you have xorg-x11-xauth installed, logout and back in again and you should see something like this

[code]
$ echo $DISPLAY
localhost:10.0
[/code]

If you don't see anything when you run the echo then X11 forwarding will not work. If you switch to another user then it's likely not to work.

[Pedzel]

Hi,

Thanks for replay.

rpm -qa | grep -i x11

xorg-x11-xauth-1.0.1-2.1
xorg-x11-filesystem-7.1-2.fc6
xorg-x11-xfs-1.0.2-4
xorg-x11-font-utils-7.1-2
libX11-1.0.3-11.el5
libX11-1.0.3-11.el5

echo $DISPLAY
localhost:10.0


When i launch the virt-manager from root :

The application 'virt-manager.py' lost its connection to the display localhost:10.0;
most likely the X server was shut down or you killed/destroyed
the application.

When i launch it from my user account nothing happens. NO error is being displayed and no manager appears.

X11 forwarding is enabled and putty is set properly.

Thx

[TrevorH]

I just tried it here over ssh and I ran virt-manager as myself. It did appear to hang but after about 15 seconds I got a pop-up prompt asking me for the root password. My connection to the server is pretty fast so maybe it might take longer. The password prompt is done using a different package but I can't find out what that is with a quick search

[Pedzel]

Hi Trevor,

It's strange. I tested exactly same settings on test server. Everything works fine. When i go to the production it does not work. The only difference between them is that on testing i have straight root login and on production i have to log into user and then su -.

Any ideas?

[TrevorH]

I can understand it not working when you su to root first as connections to the X server from different users are not allowed by default. The bit I do not understand is why you do not see a password prompt when running it as a normal user.

[Pedzel]

Ah OK. did not get you previously.

The same situation with system-config-lvm :/

Here is the part of sshd_config :

# Accept locale-related environment variables
AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
AcceptEnv LC_IDENTIFICATION LC_ALL
#AllowTcpForwarding yes
#GatewayPorts no
#X11Forwarding no
X11Forwarding yes
X11DisplayOffset 10
#X11UseLocalhost yes
#PrintMotd yes
#PrintLastLog yes
#TCPKeepAlive yes
#UseLogin no
#UsePrivilegeSeparation yes
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#ShowPatchLevel no
#UseDNS yes
#PidFile /var/run/sshd.pid
#MaxStartups 10
#PermitTunnel no
#ChrootDirectory none

Not sure what i could mess here up :/
Everything look fine here for me.

[TrevorH]

OK, got it, you need to install the package usermode-1.88-3.el5.2 (or whatever the latest version is).

[Pedzel]

Trevor,

I do not have to install anything :)
Sorry for wasting your time. The problem was in putty. do not know the reason of that but i deleted the X11 location and it started to work :)
On testing machine i deleted the X11 location and it stopped working.

If you know the reason of that i would be greateful if you could share it with me :)

Thank you for your time and sorry once more ;)

Sorry for typos but i have different language installed right now ;)
Have a nice day.

[Pedzel]

Forgot to add. Mark as solved.