This page intends to allow remote sessions using "X Display Manager Control Protocol" (XDMCP). See the GDM documention for more information on the parameters: https://help.gnome.org/admin/gdm/3.26/gdm.html#xdmcpsection.
Setup graphical logins
/etc/X11/xdm/xdm-config and comment out:
So it will be:
/etc/X11/xdm/Xaccess to allow any host to get
a login window. Look for a line that looks like this:
* #any host can get a login window
and remove the hash '#' sign at the beginning of the line.
In case you have multiple network interfaces also add a line like this:
Where 192.168.0.10 should be you server IP address.
Then reboot or restart your X server and the xdm daemon.
/etc/gdm/custom.conf to include:
[xdmcp] Enable=true Port=177
Or if using the inittab method, login as root on another tty and
telinit 3 telinit 5 && exit
Support for this feature seems to be very buggy. Lightdm is probably an easier choice.
Edit 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
kdm.service so the change you just made takes effect.
Enable the XDMCP Server:
[XDMCPServer] enabled=true port=177
On a headless system, disable the automatic start of one seat so that LightDM can run in the background:
Accessing X from a remote machine on your LAN
You can access your login manager on the network computer 192.168.0.10 via the following command. TCP and UDP streams are opened. So it is not possible to access the login manager via an SSH connection.
$ Xnest -query 192.168.0.10 -geometry 1280x1024 :1
Or, with Xephyr, if you experience refreshing problems with Xnest:
$ Xephyr -query 192.168.0.10 -screen 1280x1024 -br -reset -terminate :1
Or, if you are on runlevel 3
$ X -query server address
Xserver should recognize your monitor and set appropriate resolution.
After allowing XDMCP access as described above, edit
/etc/X11/xdm/Xservers and comment out:
#:0 local /usr/bin/X :0
Then launch XDM as root, e.g.
xdm -config /etc/X11/xdm/archlinux/xdm-config
Thin client setup
Example GUI-based Clients
- Xming for Windows
Session declined: Maximum Number of Sessions Reached
/etc/gdm/custom.conf and add/increase the maximum sessions.
[xdmcp] Enable=true MaxSessions=2