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Hi Friends, I am Sandeep CC and some people know me as System Administrator. I have started my professional career from 2008. I have been working as System Administrator on Linux Server and Windows Client. I am here to share my Knowledge in which I have experienced and which I have come across till now, It could be help to you people. In case anything wrong or any improvements in my post steps, Please comment to the post, Feel free to contact me by posting comments on this blog. Thanks and Regards, Sandeep CC

Wednesday, August 11, 2010

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


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)

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:
Change to:

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

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= (Win Machine IP, In win machine must install xming s/w)
env |grep DIS (In this should show as DIS=


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
[root@sandeeplinux3 ~]# /usr/bin/X11/Xnest -query -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 -d -p udp --dport 177 -j ACCEPT
-A RH-Firewall-1-INPUT -s -d -p tcp --dport 6000:6005 -j ACCEPT
-A RH-Firewall-1-INPUT -s -d -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 (xterminal sever IP) → Next → Next → Finish. → 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


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