Ubuntu – Remote x-server with ssh -X


I am trying to start a remote gnome session using: ssh -X username@ gnome-session

Both client and server are Ubuntu version 12.04

I get the following (and not a lot happens)…


(gnome-settings-daemon:3572): color-plugin-WARNING **: failed to get contents of /sys/class/dmi/id/board_version: Failed to open file '/sys/class/dmi/id/board_version': No such file or directory

** (gnome-settings-daemon:3572): WARNING **: You can only run one xsettings manager at a time; exiting

** (gnome-settings-daemon:3572): WARNING **: Unable to start xsettings manager: Could not initialize xsettings manager.
compiz (core) - Error: Screen 0 on display "localhost:10.0" already has a window manager; try using the --replace option to replace the current window manager.
Initializing nautilus-gdu extension
Created new window in existing browser session.
** Message: applet now removed from the notification area
** Message: using fallback from indicator to GtkStatusIcon

(gnome-settings-daemon:3572): keyboard-plugin-WARNING **: Failed to set the keyboard layouts: GDBus.Error:org.freedesktop.Accounts.Error.PermissionDenied: Not authorized

** (gnome-settings-daemon:3572): WARNING **: Failed to connect context: Connection refused

(gnome-settings-daemon:3572): clipboard-plugin-WARNING **: Clipboard manager is already running.

(gnome-settings-daemon:3572): color-plugin-WARNING **: failed to create device: GDBus.Error:org.freedesktop.ColorManager.Failed: failed to obtain org.freedesktop.color-manager.create-device auth

(gnome-settings-daemon:3572): color-plugin-WARNING **: GDBus.Error:org.freedesktop.ColorManager.Failed: failed to obtain org.freedesktop.color-manager.create-profile auth

(gnome-settings-daemon:3572): color-plugin-WARNING **: no xrandr-Samsung Electric Company-SAMSUNG device found: Failed to find output xrandr-Samsung Electric Company-SAMSUNG
Shutting down nautilus-gdu extension

** (gnome-settings-daemon:3572): WARNING **: Failed to connect context: Connection refused
Connection failure: Connection refused
pa_context_connect() failed: Connection refused

Best Answer

I assume that what you are trying to do is start a complete remote Gnome session displaying on your local machine. This fails because you already have a local session manager controlling your X server display.

Your options are:

  1. Simply start individual remote applications using ssh -X user@ xclock

  2. Assuming XDMCP is enabled on the remote machine...

    2a. Use Xnest -query -geometry 1024x768 :1 to start a remote login session in a local window.

    2b. Use Xephyr :1 -screen 1024x768 -query which is a better X server than Xnest

  3. Also assuming XDMCP on the remote machine, configure your local machine to use the XDMCP chooser instead of the standard greeter on startup.

Enabling XDMCP is simply a case of putting


in /etc/gdm/custom.conf and restarting gdm or rebooting (assuming you are running gdm).

If you only intend to run a few applications remotely, then option 1 is simplest and continues to use SSH encrypted traffic, which none of the others do (so they are best only used on a trusted local network).

If you need to so something more complicated, then 2b (Xephyr) is may be better, but I've usually found just using ssh -X ... & for multiple remote applications to be adequate.

If you are doing everything remotely, i.e. the local machine is just a display server and doesn't do anything itself, then you need to look into using option 3, starting the XDMCP chooser instead of the standard login.

PS: As noted in the comments, both Xnest and Xephyr are applications which handle the X server protocol and put the entire session into a window. Xnest uses the functions provided by the local X server while Xephyr handles much more of the server protocol itself so is more robust. They may not be installed by default because the average user wouldn't use them.

PPS: After a little thought it's obvious how to encrypt a Xephyr or Xnest session...

ssh -X username@ Xephyr :1 -query localhost -screen 1280x1024