From LinuxIntro

xdmcp allows you to log in graphically via network using VNC. This is terminal server functionality. The following tutorial shows how to configure your xdmcp: http://wmltd.co.uk/index.php/products/nomachine_thin_client/setting_up_x

[edit] For SUSE

[edit] For KDM

• enable xinetd's vnc service

Look at /etc/xinet.d/vnc, outcomment the line saying disable=yes from the first vnc section. It should look like this:

service vnc1
{
        #disable        = yes
        socket_type     = stream
        protocol        = tcp
        wait            = no
        user            = nobody
        server          = /usr/bin/Xvnc
        server_args     = -SecurityTypes None -inetd -once -query localhost -geometry 1024x768 -depth 16
        type            = UNLISTED
        port            = 5901
}

• allow your display manager to serve xdmcp:

Edit /opt/kde3/share/config/kdmrc. In the [xdmcp] section, make sure enable is set to true:

enable=true

• set yast2 -> System -> /etc/sysconfig editor -> Desktop -> Display Manager -> DISPLAYMANAGER_REMOTE_ACCESS to true
• restart the services (killing your login)

rcxinetd restart
rcxdm restart

• connect with vncviewer localhost:1

[edit] See also

• XDMCP how to
• http://wmltd.co.uk/index.php/products/nomachine_thin_client/setting_up_x - how it works, in clear words
• The Linux Terminal Server Project is based on xdmcp.