[CentOS] Remote X connection to CentOS 5.5 using Xming -ac

Tue Jun 15 19:16:29 UTC 2010

If you setup X11 forwarding in PuTTY, then double-click on a saved
putty session, it will clear out the X11 forwarding and use the
settings from the saved session (no X forwarding).  If X forwarding is
properly enabled, you should not have to set the DISPLAY variable on
the remote side.

You don't need the X server or anything else on the remote server.
Default firewall will have no effect either.  Also, make sure to
reload sshd after changing the settings (service sshd reload).

On Tue, Jun 15, 2010 at 3:10 PM, Alexander Farber
<alexander.farber at gmail.com> wrote:
> Hello,
>
> I've rented a dedicated root server (SR7 at strato.de)
> and would like to run qemu at it, but get the error:
>
>  # qemu -hda install.img -cdrom install47.iso -boot d
>  Could not initialize SDL - exiting
>
> It seems that I have to establish X connection,
> so I've installed Xming at my WinXP laptop
> and at the server I have changed these 3 lines
> in the /etc/ssh/sshd_config:
>
>  X11Forwarding yes
>  X11DisplayOffset 10
>  X11UseLocalhost yes
>
> And also I have installed these Xorg packages:
>
>  # rpm -qa | grep -i xorg
>  xorg-x11-utils-7.1-2.fc6
>  xorg-x11-drv-evdev-1.0.0.5-5.el5
>  xorg-x11-drv-vesa-1.3.0-8.2.el5
>  xorg-x11-filesystem-7.1-2.fc6
>  xorg-x11-font-utils-7.1-2
>  xorg-x11-server-utils-7.1-4.fc6
>  xorg-x11-xkb-utils-1.0.2-2.1
>  xorg-x11-xfs-1.0.2-4
>  xorg-x11-fonts-base-7.1-2.1.el5
>  xorg-x11-drv-keyboard-1.1.0-3
>  xorg-x11-server-Xorg-1.1.1-48.76.el5_5.1
>  xorg-x11-drv-mouse-1.1.1-1.1
>  xorg-x11-drv-void-1.1.0-3.1
>
> Then I've restarted the server and run PuTTY
> to connect to it, where I have checked the
> Connection->SSH->X11->Enable X11 forwarding
>
> (Sorry for mentioning all this Windows stuff,
> but I don't have a Unix desktop and also the
> problem seems to be in the CentOS config)
>
> When I connect to the CentOS machine,
> the DISPLAY variable isn't set at all.
> Shouldn't SSH set it to localhost:10.0 ?
>
> I try to set DISPLAY manually to localhost:10.0
> and my_ip_address:0.0 and I have tried
> connecting as root and as a non-root user.
>
> Still I can't run any X programs like xterm:
>
> $ echo $DISPLAY
>
> $ xterm
> xterm Xt error: Can't open display:
> xterm:  DISPLAY is not set
>
> $ export DISPLAY=localhost:10.0
> $ xterm
> xterm Xt error: Can't open display: localhost:10.0
>
> $ netstat -an |grep ESTABLISHED (my sshd listens at port 443)
> tcp        0     52 ::ffff:85.214.XXX.XXX:443
> ::ffff:88.153.153.102:2646  ESTABLISHED
> tcp        0      0 ::ffff:85.214.XXX.XXX:443
> ::ffff:88.153.153.102:2566  ESTABLISHED
>
> $ export DISPLAY=88.153.153.102:0.0
> $ xterm
> xterm Xt error: Can't open display: 88.153.153.102:0.0 (after long time)
>
> And the firewall is off:
>
> $ sudo /sbin/service iptables status
> Firewall is stopped.
>
> And I don't see anything in the Xming log (pasted below).
>
> Does anybody please have a hint for me?
> My Linux knowledge is a bit rusty :-)
>
> Should I start X somehow at the Linux side?
> (I've checked chkconfig --list, found nothing there)
>
> Regards
> Alex
>
> PS: Xming log below:
>
>
> Welcome to the Xming X Server
> Vendor: Colin Harrison
> Release: 6.9.0.31
> FreeType2: 2.3.4
> Contact: http://sourceforge.net/forum/?group_id=156984
>
> C:\Program Files\Xming\Xming.exe :0 -ac -clipboard -multiwindow
>
> XdmcpRegisterConnection: newAddress 10.216.41.31
> winAdjustVideoModeShadowGDI - Using Windows display depth of 32 bits per pixel
> winAllocateFBShadowGDI - Creating DIB with width: 1920 height: 1200 depth: 32
> winInitVisualsShadowGDI - Masks 00ff0000 0000ff00 000000ff BPRGB 8 d 24 bpp 32
> glWinInitVisuals:1596: glWinInitVisuals
> glWinInitVisualConfigs:1503: glWinInitVisualConfigs
> glWinSetVisualConfigs:1581: glWinSetVisualConfigs
> init_visuals:1055: init_visuals
> null screen fn ReparentWindow
> null screen fn RestackWindow
> InitQueue - Calling pthread_mutex_init
> InitQueue - pthread_mutex_init returned
> InitQueue - Calling pthread_cond_init
> InitQueue - pthread_cond_init returned
> winInitMultiWindowWM - Hello
> winInitMultiWindowWM - Calling pthread_mutex_lock ()
> winMultiWindowXMsgProc - Hello
> winMultiWindowXMsgProc - Calling pthread_mutex_lock ()
> glWinScreenProbe:1390: glWinScreenProbe
> fixup_visuals:1303: fixup_visuals
> init_screen_visuals:1336: init_screen_visuals
> (--) 5 mouse buttons found
> (--) Setting autorepeat to delay=500, rate=31
> (--) winConfigKeyboard - Layout: "00000407" (00000407)
> (--) Using preset keyboard for "German (Germany)" (407), type "4"
> Could not init font path element C:\Program Files\Xming/fonts/misc/,
> removing from list!
> Could not init font path element C:\Program Files\Xming/fonts/TTF/,
> removing from list!
> Could not init font path element C:\Program Files\Xming/fonts/Type1/,
> removing from list!
> Could not init font path element C:\Program Files\Xming/fonts/75dpi/,
> removing from list!
> Could not init font path element C:\Program Files\Xming/fonts/100dpi/,
> removing from list!
> Could not init font path element C:\Program Files\Xming\fonts\dejavu,
> removing from list!
> Could not init font path element C:\Program
> Files\Xming\fonts\cyrillic, removing from list!
> Could not init font path element C:\WINDOWS\Fonts, removing from list!
> winInitMultiWindowWM - pthread_mutex_lock () returned.
> winInitMultiWindowWM - pthread_mutex_unlock () returned.
> winInitMultiWindowWM - DISPLAY=127.0.0.1:0.0
> winMultiWindowXMsgProc - pthread_mutex_lock () returned.
> winMultiWindowXMsgProc - pthread_mutex_unlock () returned.
> winMultiWindowXMsgProc - DISPLAY=127.0.0.1:0.0
> winProcEstablishConnection - Hello
> winInitClipboard ()
> winProcEstablishConnection - winInitClipboard returned.
> winMultiWindowXMsgProc - XOpenDisplay () returned and successfully
> opened the display.
> winInitMultiWindowWM - XOpenDisplay () returned and successfully
> opened the display.
> winClipboardProc - Hello
> DetectUnicodeSupport - Windows XP
> winClipboardProc - DISPLAY=127.0.0.1:0.0
> winClipboardProc - XOpenDisplay () returned and successfully opened the display.
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