Acronym for Virtual Network Computing. VNC lets you export your display, and keyboard/mouse control, over the network. It was originally designed at AT&T.

Like all good GPL software there are at least three popular variants:

• RealVNC (the "original", commercially supported)
• TightVNC (concentrating on speeding up the protocol using compression)
• UltraVNC (concentrating on adding features, like Microsoft authentication & file tranfer)

Read more about VNC at Wikipedia.

Setting up your X server as a VNC server

These instructions are for Ubuntu, and were tested on 6.10.

apt-get install vnc4server

In the Modules section of your /etc/X11/xorg.conf

        Load    "vnc"

And in the Screen section:

        Option "passwordFile" "/root/.vncpasswd"

Create a password file:

sudo vncpasswd /root/.vncpasswd

And you're done. Using a VNC viewer on another machine you can now connect to your X session.

There are other ways of doing this - VNC GDM is a method of using VNC and XDMCP to give you a GDM window over VNC, and the Vino system runs a VNC session per user, which can be enabled from the GUI. You then log in with your own password.