30.3. Installation Using VNC

Now that you have installed a VNC viewer application and selected a VNC mode for use in anaconda, you are ready to begin the installation.

30.3.1. Installation Example

The easiest way to perform an installation using VNC is to connect another computer directly to the network port on the target system. The laptop on a datacenter crash cart usually fills this role. If you are performing your installation this way, make sure you follow these steps:
  1. Connect the laptop or other workstation to the target system using a crossover cable. If you are using regular patch cables, make sure you connect the two systems using a small hub or switch. Most recent Ethernet interfaces will automatically detect if they need to be crossover or not, so it may be possible to connect the two systems directly using a regular patch cable.
  2. Configure the VNC viewer system to use a RFC 1918 address with no gateway. This private network connection will only be used for the purpose of installation. Configure the VNC viewer system to be If that address is in use, just pick something else in the RFC 1918 address space that is available to you.
  3. Start the RHEL installation on the target system.
    1. Booting the installation DVD or CD.
      If booting the installation media (CD or DVD), make sure vnc is passed as a boot parameter. To add the vnc parameter, you will need a console attached to the target system that allows you to interact with the boot process. Enter the following at the prompt:
      boot: linux vnc
    2. Boot over the network.
      If the target system is configured with a static IP address, add the vnc command to the kickstart file. If the target system is using DHCP, add vncconnect=HOST to the boot arguments for the target system. HOST is the IP address or DNS host name of the VNC viewer system. Enter the following at the prompt:
      boot: linux vncconnect=HOST
  4. When prompted for the network configuration on the target system, assign it an available RFC 1918 address in the same network you used for the VNC viewer system. For example,


    This IP address is only used during installation. You will have an opportunity to configure the final network settings, if any, later in the installer.
  5. Once the installer indicates it is starting anaconda, you will be instructed to connect to the system using the VNC viewer. Connect to the viewer and follow the graphical installation mode instructions found in the product documentation.

30.3.2. Kickstart Considerations

If your target system will be booting over the network, VNC is still available. Just add the vnc command to the kickstart file for the system. You will be able to connect to the target system using your VNC viewer and monitor the installation progress. The address to use is the one the system is configured with via the kickstart file.
If you are using DHCP for the target system, the reverse vncconnect method may work better for you. Rather than adding the vnc boot parameter to the kickstart file, add the vncconnect=HOST parameter to the list of boot arguments for the target system. For HOST, put the IP address or DNS host name of the VNC viewer system. See the next section for more details on using the vncconnect mode.

30.3.3. Firewall Considerations

If you are performing the installation where the VNC viewer system is a workstation on a different subnet from the target system, you may run in to network routing problems. VNC works fine so long as your viewer system has a route to the target system and ports 5900 and 5901 are open. If your environment has a firewall, make sure ports 5900 and 5901 are open between your workstation and the target system.
In addition to passing the vnc boot parameter, you may also want to pass the vncpassword parameter in these scenarios. While the password is sent in plain text over the network, it does provide an extra step before a viewer can connect to a system. Once the viewer connects to the target system over VNC, no other connections are permitted. These limitations are usually sufficient for installation purposes.


Be sure to use a temporary password for the vncpassword option. It should not be a password you use on any systems, especially a real root password.
If you continue to have trouble, consider using the vncconnect parameter. In this mode of operation, you start the viewer on your system first telling it to listen for an incoming connection. Pass vncconnect=HOST at the boot prompt and the installer will attempt to connect to the specified HOST (either a hostname or IP address).