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Related YoLinux Tutorials:
°Linux in a MS/Windows Network
°Linux Networking
°Linux Sys Admin
°YoLinux Tutorials Index
Free Information Technology Magazines and Document Downloads
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| Linux configuration for a GUI login: |
Typically Linux configures the choice of a text console login or a graphical GUI login in 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.
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# 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:
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(Partial file listing)
Note that this shows a run level of "5" for a Red Hat / Fedora / CentOS based configuration.
Ubuntu:
- Start GDM manually with the command: /etc/init.d/gdm
(This can be added to the system init process: ln -s /etc/init.d/gdm /etc/rc2.d/S13gdm)
or
- add to /etc/inittab or /etc/rc.local
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x:2:respawn:/usr/sbin/gdm
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Ubuntu uses runlevel 2-5 as regular multi-user mode.
Also see the YoLinux.com Linux init process tutorial.
| Granting MS/Windows users remote GUI access to your system: |
XDM login manager:
- Edit file:
- Red Hat: /etc/X11/xdm/Xaccess
- Suse: /usr/X11R6/lib/X11/xdm/Xaccess
Change from:
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# * #any host can get a login window
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To:
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* #any host can get a login window
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- Edit file: /etc/X11/xdm/xdm-config
Change last line from:
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!DisplayManager.requestPort: 0
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To:
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DisplayManager.requestPort: 0
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System default for RHEL4/FC3.
GDM login manager:
- Edit file:
- Red Hat Enterprise 5, CentOS 5: /etc/gdm/custom.conf
Note: RHEL5 only uses this file as XDM is no longer supported.
Add two enties to the existing categories:
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[xdmcp]
Enable=true
[security]
DisallowTCP=false
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One can also use the GUI config tool /usr/sbin/gdmsetup.
- Red Hat Enterprise 3/4, CentOS 3/4, Fedora 1-6: /etc/X11/gdm/gdm.conf
Change last line from:
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To:
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One can also use the GUI config tool gdmsetup.
- Restart X-Windows:
- [root]# init 3
- [root]# 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
gdmsetup: This GUI will edit the configuration GDM configuration file.
- Red Hat Enterprise 5, CentOS 5: /etc/gdm/custom.conf
- Red Hat Enterprise 3/4, CentOS 3/4, Fedora 1-6: /etc/X11/gdm/gdm.conf
Select the check box "Enable XDMCP":
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| Remote X server access for MS/Windows: |
Open Source MS/Windows PC X-Windows server software:
Commercial MS/Windows PC X-Windows server software:
Also see accessing Linux from Microsoft Windows for more remote X-Windows configuration information.
| Remote X server access for Linux: |
Use the X-Windows Xnest command to connect.
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/usr/bin/X11/Xnest -query computer-node-name -geometry 1280x1024 :1
Example using option "-geometry 850x680".
[Potential Pitfall]: If your get the following error message:
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Fatal server error:
Server is already active for display 0
This means you forgot the ":1" at the end of the command and it defaulted to :0 which is your current desktop window thus causing a conflict.
Red Hat / Fedora / CentOS distributions require package xorg-x11-Xnest
- 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)
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