HOWTO XDMCP

From Gentoo Linux Wiki

[edit] Introduction

XDMCP stands for "X Display Manager Control Protocol" and is a network protocol. It allows a way of running X-Terminal on your PC (or Mac) and uses the X Server to provide a client/server interface between display hardware (the mouse, keyboard, and video displays) and the desktop environment while also providing both the windowing infrastructure and a standardized application interface. The X-Terminal can be displayed with an individual window or multiple windows, based on your X window system's software capabilities and setup.

[edit] Editing Configuration

On your X-Server, you must tweak the configuration of your graphical login manager (displaymanager).

[edit] For XDM

You need to comment out DisplayManager.requestPort: 0 in your configfile xdm-config:

! SECURITY: do not listen for XDMCP or Chooser requests
! Comment out this line if you want to manage X terminals with xdm
#  DisplayManager.requestPort: 0

I also had to remove a commented line in the Xaccess configfile:

*                                       #any host can get a login window

[edit] For GDM

You need to change the [xdmcp]-section in your configfile gdm.conf:

--For ME The config file is /etc/X11/gdm/custom.conf

[xdmcp]
Enable=true

Depending on how your gdm.conf/custom.conf is set up, you might also need to add or change the [greeter] section as shown below. Without this, you will not be able to XDMCP in to your server.

[greeter]
Browser=true

[edit] For KDM

You need to change the [xdmcp]-section in your configfile kdmrc:

[Xdmcp]
Enable = true

[edit] Restarting XDM/KDM/GDM

You can restart the display manager by running $ /etc/init.d/xdm restart

[edit] How to use XDMCP

On the remote machine you can either use Xnest or simply X:

$ X -ac -query servername :1

or

$ Xnest -ac -query servername :1

Replace servername with your servername or IP. :1 is the display number. (:0 should be your running X-Server)