Setup CentOS / Redhat as a VNC server for all users

Lets suppose you have a Linux server you would like the users to access via VNC. On a basic setup a user may need to SSH into the server and find out what display socket they will be connecting to. This is overhead that can be avoided. Using the method below a user can connect directly to the server using a VNC client as their first and only step.

Open the ports:

vi /etc/sysconfig/iptables

Add the following lines

-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 5900 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m udp -p udp --dport 5900 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 5901 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m udp -p udp --dport 5901 -j ACCEPT

Restart the firewall service:

service iptables restart

Be sure vnc-server and other components are installed:

yum –ty install vnc-server xinetd

Also grab vnc-ltsp-conf and install it using:
rpm –Uvh vnc-ltsp-config-4.0-4.el5.noarch.rpm

Start the services and configure to start on reboot:

service vncserver start

Check the service configuration in webmin or using system-config-services or using these commands:

/sbin/chkconfig xinetd on
/sbin/chkconfig vncts on
/sbin/chkconfig vncserver on
/sbin/service xinetd restart

Configuration:

As root edit the file "/etc/gdm/custom.conf"

To the next blank line below the "[security]" section add "DisallowTCP=false"

To the next blank line below the "[xdmcp]" section add "Enable=true"

Make sure you are in a position to either run "gdm-restart" for default Gnome installs or just reboot the CentOS box.

Valid users should now be able to use the VNC client to connect to the server.