Launching GUI on RHEL?

Question

logged in to rhel 6.4 using Putty using ssh. Installed the GNOME desktop environment, using this command:

yum groupinstall "X Window System" "KDE Desktop"

Now, followed steps below:

1. Run the following command to edit the /etc/inittab file: vi /etc/inittab
2. Press the *I* key to enter insert mode.
3. Find the line that includes the text initdefault. Change the numeral 3 to 5.

4. Type :wq and press the *Enter* key to save the file and exit the *vi* text editor.

   Reboot the system using the reboot command. Your system will restart and present a graphical login

The problem is after reboot, grapghical login is not displayed. I tried running command vncserver got output:

New 'z3-9-5-126-154:2 (root)' desktop is z3-9-5-126-154:2

Starting applications specified in /root/.vnc/xstartup
Log file is /root/.vnc/z3-9-5-126-154:2.log

now, from windows laptop, I am trying to connect using vnc viewer but not able to connect. Please help me how to launch GUI mode.

Answer 1

It sounds like you have setup runlevel 5 (i.e. graphical login) just fine. Normally to access the GUI you'd have a monitor hooked up to the system or allow X connections over the network via XDM or the like.

The following assumes you have a vnc server running. This is a pretty good assumption as you show it running with your command.

I would guess that the issue is that iptables (the host based firewall on linux) is blocking access for the vnc server.

You can run the following command (this will open access to the whole network):

/sbin/iptables -I INPUT -m tcp -p tcp --dport 5900 -j ACCEPT

If you want only from a specific machine or network then use this rule but substitute MY_NETWORK for the ipaddres or cidr block that you want to allow:

/sbin/iptables -I INPUT -m tcp -p tcp --dport 5900 --src MY_NETWORK -j ACCEPT

Try to connect again with VNC. If everything works then you can save your iptables changes like so:

/bin/cp /etc/sysconfig/iptables /etc/sysconfig/iptables-`date -I`
/sbin/iptables-save > /etc/sysconfig/iptables

This will make a backup of your current iptables config and then write out the new one.

Answer 2

Some comments:

1.) When you say 'graphical login is not displayed', do you mean you can't VNC into the host? Or is it hooked up to a monitor and you can't see anything on the screen?

2.) You really shouldn't be running the Xvnc as root, and logging in as root in a graphical environment. Start as a regular user, and only use 'su' or 'sudo' to run processes with escalated privileges.