What is a VNC (Virtual Network Connection)?

VNC allows remote connections from a client computer to a server, creating a virtual desktop (desktop image) of the server screen on the client computer screen. The user of the client computer can work almost as if he or she were sitting in front of the screen of the remote computer. VNC continuously compresses and transfers screen shots from the server to the client, which makes for a much faster experience than normal X-forwarding. VNC allows a remote observer to connect to the LOFAR computer cluster.

How Do I Get the Necessary Software?

Windows

VNC comes with most Linux distributions and is easily set up. Mac and Windows users should download and install a VNC Viewer.

VNC for Windows is freely available from TightVNC (www.tightvnc.com) or from RealVNC (www.realvnc.com).

You will also need an SSH client. An SSH client allows you to make a secure SSH connection from your work/home machine to the LOFAR Linux machines. That is, with SSH client software running on your computer, you can open a terminal window to the remote Linux computer. For Windows users, PuTTY is a freeware SSH client. It is available from www.chiark.greenend.org.uk/~sgtatham/putty/download.html. Although other SSH client software exists (e.g. SSH Secure Shell, Secure CRT), our instructions assume you are using PuTTY.

Thus, remote Window users should:

Download and install VNC unless it is already installed. You need only install the VNC viewer. Download and install PuTTY unless it is already installed on your machine.

Next, start up PuTTY on your Windows machine. A PuTTY Configuration window will appear

In the configuration window, specify the host name, portal.lofar.eu and click on Open to obtain a terminal window to the host. (After specifying the host name, one can choose Save to save the session for future use. If the host name already appears among the Saved Sessions, double click on the host name to open a terminal window to that host.)

Mac OS X

For Mac users, Chicken of the VNC is a good VNC client and is available from sourceforge.net/projects/cotvnc.

Download the Chicken of the VNC disk image file (dmg) and then double-click it to mount it on your desktop. Then drag the Chicken of the VNC icon to your Mac's Applications folder.

Mac OS X includes an SSH client. You can open a terminal by launching either Terminal or X11, both of which are in your Mac's Applications > Utilities folder.

Now

Open a terminal on your local computer and type:

ssh USER@portal.lofar.eu

If you are not using an SSH agent, you will be asked to enter your account username and password (below)