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Revision as of 16:38, 9 January 2010 by Sandstorm (talk | contribs) (Troubleshooting)
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This page intends to allow remote sessions using "X Display Manager Control Protocol" (XDMCP).


One way to start the X server is through kdm, and if you want to be able to login remotely to your kde session from a remote machine, you need to allow xdmcp. To do this edit your kdmrc ( /opt/kde/share/config/kdm/kdmrc [KDE 3x] or /usr/share/config/kdm/kdmrc (KDE 4x] ) and at the end there should be something like this:


Then you need to restart your X server so the change you just made takes effect:

/etc/rc.d/kdm restart


If you prefer to use GDM instead of KDM, the manipulation is basically the same. Edit /etc/gdm/custom.conf according to the following snippet:


The restart the Gnome Display Manager:

/etc/rc.d/gdm restart

It is even possible to do all this using the graphical GDM configuration tool (gdmsetup) from a local X session or through the network using ssh -X.

Now you should be able to login remotely using your prefered session/WM. Enjoy!


SLiM doesn't support Xdmcp.


XDMCP fatal error: Manager unwilling Host unwilling

When connecting to the X server from a remote host you get:

Fatal server error:
XDMCP fatal error: Manager unwilling Host unwilling

Your current settings are too restrictive. Edit /etc/hosts.allow to allow remote connexions to display manager. Add this line if you use GDM:

 gdm: ALL


This is usually caused by an entry missing from the "/etc/kde3/kdm/Xaccess" file. This file controls which machines can connect to the server via KDM. The trick is to add a line that starts with an Aster- isk '*'. Look for a line that looks like:

      # *                                     #any host can get a login window

and remove the hash '#' sign at the beginning of the line. Then, you need to restart KDM.

/etc/rc.d/kdm restart

Test in Ubuntu Server 8.04. Source: http://www.bogor.net/idkf/idkf-wireless/aplikasi/linux/low-cost-thinclient/lts_tsguide_v2.2.txt

Session declined: Maximum Number of Sessions Reached

Edit /etc/gdm/custom.conf and add/increase the maximum sessions.