1. As root at the prompt in the VM's text console, type in rpm -q vnc-server gdm. The package names vnc-server and gdm should appear, with their version numbers specified.

   If these package names are displayed, the appropriate packages are already installed. If you see a message saying that one of the packages is not installed, then you may not have selected the graphical desktop options during installation. You will need to install these packages before you can continue. See the appropriate Red Hat Linux x86 Installation Guide for details regarding installing additional software on your VM.

2. Open the GDM configuration file with your preferred text editor and add the following lines to the file:

   [server-VNC]
   name=VNC Server
   command=/usr/bin/Xvnc -SecurityTypes None -geometry 1024x768 -depth 16 -BlacklistTimeout 0
   flexible=true
   

   • With configuration files as found on Red Hat Linux 3 and 4, this should be added above the [server-Standard section.

   • With configuration files as found on Red Hat Linux 5, this should be added into the empty [servers] section.

3. Modify the configuration so that the Xvnc server is used instead of the standard X server:

   • If you are using Red Hat Linux 3 or 4, there will be a line just above that says:

     0=Standard
     

     Modify it to read:

     0=VNC
     

   • If you are using Red Hat Linux 5 or greater, you will need to add the above line just below the [servers] section and before the [server-VNC] section.

4. Save and close the file.

To customize Red Hat-based VMs firewall to open the VNC port

1. For Red Hat Linux 3, use redhat-config-securitylevel-tui.

   For Red Hat Linux 4 and 5, use system-config-securitylevel-tui.

2. Select “Customize” and add 5900 to the other ports list.

1. Open the GDM configuration file with your preferred text editor. Please refer to Section 4.7.1.1, “Determining the location of your VNC configuration file” for information about determining the location of this file.

2. Find the [server-VNC] section you added above.

3. Edit the command line to read, for example,

   command=/usr/bin/Xvnc -SecurityTypes None -geometry 800x600
   

   where the value of the -geometry parameter can be any valid screen width and height.

4. Save and close the file.

1. Open a text console on the VM and run the YaST utility:

   # yast
   		

   Note

   Due to the complex control characters used to draw the YaST configuration screens, your screen usually becomes corrupted while using the text-mode YaST configuration tools. For example, you will be unable to see portions of the display, for example. In the steps that follow, use the key combination Ctrl+L to redraw the display and remove artifacts when necessary.

2. Use the arrow keys to select Network Services in the left menu, then Tab to the right menu and use the arrow keys to select Remote Administration. Press Enter.

3. In the Remote Administration screen, Tab to the Remote Administration Settings section. Use the arrow keys to select Allow Remote Administration and press Enter to place an X in the checkbox.

4. Tab to the Firewall Settings section. Use the arrow keys to select Open Port in Firewall and press Enter to place an X in the checkbox.

5. Tab to the Finish button and press Enter.

6. A messsage box appears telling you that you will need to restart the display manager for your settings to take effect. Press Enter to acknowledge the message.

7. The original top-level menu of YaST appears. Tab to the Quit button and press Enter.

1. Open the file /etc/xinetd.d/vnc in your preferred text editor.

   The file contains sections like the following:

   service vnc1
   {
     socket_type = stream
     protocol    = tcp
     wait        = no
     user        = nobody
     server      = /usr/X11R6/bin/Xvnc
     server_args = :42 -inetd -once -query localhost -geometry 1024x768 -depth 16
     type        = UNLISTED
     port        = 5901
   }
   

2. Make the following changes:

   • edit the port line to read port = 5900

   • edit the server_args line to include the argument -BlacklistTimeout 0 at the end

3. Save and close the file.

4. Restart the display manager and xinetd service with the following commands:

   /etc/init.d/xinetd restart
   rcxdm restart
   

To customize SLES-based VMs firewall to open the VNC port

1. Open a text console on the VM and run the YaST utility:

   # yast
   		

   Note

   Due to the complex control characters used to draw the YaST configuration screens, your screen usually becomes corrupted while using the text-mode YaST configuration tools. For example, you will be unable to see portions of the display, for example. In the steps that follow, use the key combination Ctrl+L to redraw the display and remove artifacts when necessary.

2. Use the arrow keys to select Security and Users in the left menu, then Tab to the right menu and use the arrow keys to select Firewall. Press Enter.

3. In the Firewall screen, Tab to the Firewall Configuration: Settings section. Use the arrow keys to select the Allowed Services in the left menu.

4. Tab to the Firewall Configuration: Allowed Services fields on the right. Use the arrow keys to select the Advanced... button (near the bottom right, just above the Next button) and press Enter.

5. In the Additional Allowed Ports screen, type 5900 in the TCP Ports field. Tab to the OK button and press Enter.

6. Tab back to the list of screens on the left side and use the arrow keys to select Start-Up. Tab back to the right and Tab to the Save Settings and Restart Firewall Now button and press Enter.

7. Tab to the Next button and press Enter, then in the Summary screen Tab to the Accept button and press Enter, and finally on the top-level YaST screen Tab to the Quit button and press Enter.

8. Restart the display manager and xinetd service with the following commands:

   /etc/init.d/xinetd restart
   rcxdm restart
   

1. Open the /etc/xinetd.d/vnc file with your preferred text editor and find the service_vnc1 section (corresponding to displayID 1).

2. Edit the -geometry argument in the server-args line to the desired display resolution. For example,

   server_args  = :42 -inetd -once -query localhost -geometry 800x600 -depth 16
   

   where the value of the -geometry parameter can be any valid screen width and height.

3. Save and close the file.

4. Restart the vnc server:

   /etc/init.d/xinetd restart
   rcxdm restart