X-Terminal & Linux login with a XP Machine and XDMCP on REDHAT LINUX

X-Terminal

Setup With Windows Machine:
Download X-ming software/tool from http://sourceforge.net/projects/xming/ and Install on windows XP system. And after Linux configuration open Xming in windows system.

Setup With Linux Machine:

Linux Configuration For a GUI Login
[root@sandeeplinux3 ~]#cat /etc/inittab
#
# inittab This file describes how the INIT process should set up
# the system in a certain run-level.
#
# Author: Miquel van Smoorenburg,
# Modified for RHS Linux by Marc Ewing and Donnie Barnes
#
# Default runlevel. The runlevels used by RHS are:
# 0 - halt (Do NOT set initdefault to this)
# 1 - Single user mode
# 2 - Multiuser, without NFS (The same as 3, if you do not have networking)
# 3 - Full multiuser mode
# 4 - unused
# 5 - X11
# 6 - reboot (Do NOT set initdefault to this)
id:5:initdefault:

Typically Linux Configures the choice of a test console login or a graphical GUI login the init script Configuration file /etc/inittab. In order to allow remote a GUI login, the system itself must be configured for a X11 GUI login.

Granting MS/Windows users remote GUI access to your system:
XDM login manager:
Edit file:

[root@sandeeplinux3 ~]#vi /etc/X11/xdm/Xaccess
Change from
# * #any host can get a login window
Change To
* #any host can get a login window

Edit file:

[root@sandeeplinux3 ~]#vi /etc/X11/xdm/xdm-config
Change from:
!DisplayManager.requestPort: 0
Change to:
DisplayManager.requestPort: 0

GDM Login manager:

Edit file:

[root@sandeeplinux3 ~]# vi /etc/X11/gdm/gdm.conf
Change last line from:
[xdmcp]
Enable=false
Change to:
[xdmcp]
Enable=true

Restart X-windows:
[root@sandeeplinux3 ~]# init 3
[root@sandeeplinux3 ~]# init 5

Note:
You can use the config tool /usr/sbin/gdmsetup to configure GDM
You can test the GDM login screen locally: X -query localhost :1

Testing By Linux Machine:

export DISPLAY=192.168.1.212:0 (Win Machine IP, In win machine must install xming s/w)
env |grep DIS (In this should show as DIS=192.168.1.212:0.0)
xterm

GUI REMOTE DESKTOP FROM LINUX TO WINDOWS

Configure above steps for Windows and Linux Machine and also follow next steps:

Linux Setup:

Click on link http://linuxsoft.cern.ch/scientific/42/x86_64/errata/bugfix-43.old/RPMS/ and download “xorg-x11-Xnest-6.8.2-1.EL.13.20.x86_64.rpm” package and install on linux machine.

Installation Steps:

[root@sandeeplinux3 ~]# rpm -qa |grep xorg-x11-Xnest-6.8.2-1.EL.13.20.x86_64.rpm (1st check whether package has installed default, if not installed then install that package)

[root@sandeeplinux3 ~]# rpm -i xorg-x11-Xnest-6.8.2-1.EL.13.20.x86_64.rpm (Install Xnest package)

Remote X Server access for Linux:

Use the X-Windows Xnest command to connect
Example:
[root@sandeeplinux3 ~]# /usr/bin/X11/Xnest -query 192.168.1.212:0 -geometry 1280x1024 :1

If your get the following error message:

Fatal server error:
Server is already active for display 0

This means you forget the “:1” at the end of the command and it defaulted to :0 which is your current desktop window thus causing a conflict.

X-Terminal & Remote Desktop with Firewall Enabling:

Make sure the system firewall rules allow XDMCP protocol to pass.
List firewall rules: iptables -L
Flush all firewall rules: iptables -F
The following ports and protocols must be able to pass through the firewall:
UDP: 177 (XDMCP)
TCP: 6000-6005 (X11 protocol)
TCP: 7100 (xfs: X font server)

Edit Iptable file:
[root@sandeeplinux3 ~]# vi /etc/sysconfig/iptables

-A RH-Firewall-1-INPUT -s 192.168.1.0/24 -d 192.168.1.0/24 -p udp --dport 177 -j ACCEPT
-A RH-Firewall-1-INPUT -s 192.168.1.0/24 -d 192.168.1.0/24 -p tcp --dport 6000:6005 -j ACCEPT
-A RH-Firewall-1-INPUT -s 192.168.1.0/24 -d 192.168.1.0/24 -p tcp --dport 7100 -j ACCEPT
:wq [save & exit]

[root@sandeeplinux3 ~]# service iptables restart
Flushing firewall rules: [ OK ]
Setting chains to policy ACCEPT: filter [ OK ]
Unloading iptables modules: [ OK ]
Applying iptables firewall rules: [ OK ]

Windows Setup:
Note: In windows system xming must be installed, keep Xming & Xlaunch on desktop.

Windows Desktop → click on Xlaunch → Select one window → Next → Select open session via XDMCP → connect to host 192.168.1.11 (xterminal sever IP) → Next → Next → Finish. → 192.168.1.11 system remote desktop will launch → give linux machine user name → password → Enter. → now remote desktop has connected on Windows XP machine from linux.

Thanks and Regards,
Sandeep CC