Using VNC

What is VNC?

VNC stands for "Virtual Network Computer". It is a tool for viewing your UNIX or Windows desktop remotely. There are two parts of VNC: the server and the viewer. In the UNIX lab we manage your VNC server making sure that it is running correctly and restarted whenever machines in the lab are rebooted. The viewer is used to connect from a remote computer and view your desktop.

When you were assigned an account you were given an IP address (four numbers separated by dots beginning with "10.") and a display number (separated from the IP address by a colon). Throughout this discussion I will assume you were assigned 10.5.1.2:3 which would be IP address 10.5.1.2 and display number 3. You will need these number to connect to your VNC server. You have many choices of viewers but we will discuss three: a web applet and the Windows TightVNC client and the UNIX lab vnc client. In addition, in the last section, we will describe how to tunnel your VNC session from off campus (or for more secure use on campus).

From a web browser

This is the simplest way to connect to your VNC session and can be used anywhere on campus. To connect to your VNC session open a web browser (Internet Explore, Mozilla and Firefox all work fine for this) and enter the following URL:

http://<ipaddress>:580<displayNumber>

For example if you were assigned IP address 10.5.1.2 display number 3 you would enter:

http://10.5.1.2:5803

At this point you should be prompted for a password. Enter your assigned password and click the OK button. Important note: When you are done simply close the browser window do not log out of your UNIX desktop session or your VNC session will be rendered useless.

Using the Windows TightVNC viewer

Download and install TightVNC on your windows computer. Find the install location in your windows Start menu. Select VNC viewer and enter the connection IP address and display number you were assigned (with the colon between them). Sorry, I don't do windows so I can't be more specific.

Using the UNIX lab VNC viewer

Simply enter the command:


vncviewer <ipaddress>:<displayNumber>

For example if you were assigned IP address 10.5.1.2 display number 3 you would enter:


vncviewer 10.5.1.2:3

You might wonder why you would want to use VNC within the lab. Many people like to keep everything they are doing open in their VNC session. Or, for example, you might have been editing a file in your VNC session remotely and need to save and exit the editor but have already arrived in class.

Securing VNC

The campus firewall does not permit VNC connections into the UNIX lab unless they are tunneled. VNC can be tunneled through SSH, the Secure SHell system. If you are converned about security you should tunnel your VNC session even when you are working on campus. To do so, follow these simple steps.

From a Windows machine:

Download and install SSH from SSH.org, the non-commercial version is generally best.
Download and install VNC, I currently recommend TightVNC, as it has a few newer features.
Start SSH, open the Edit menu and click Settings.
Click on "Tunneling" in the left-hand pane. (see figure 1)
Click the "Add" button in the right-hand pane under "Outgoing". (see figure 1)
In the "Name" box, put "VNC" (see figure 2)
Set "Type:" to "TCP" (see figure 2)
Set "Listen port:" to "5900" (see figure 2)
Leave "Allow Local Connections Only" enabled. (see figure 2)
Set "Destination Port:" to "590x", where x is the display number of your VNC server. (see figure 2)
Click "Ok" to add the tunnel.
Connect to the machine that houses your VNC server in SSH.
Start VNCViewer, connect to "localhost:0" and enter your password.
Congratulations, you are now running VNC via a secure shell connection.

From a Linux/Unix machine:

Download and install SSH from SSH.org (if you don't already have SSH installed)
Download and install VNC, I currently recommend TightVNC, as it has a few newer features.
Open a new terminal.
Enter the following command: ssh -L 5900:<destination>:590x localhost where x is the display number of your VNC server.
Open another terminal.
Enter vncviewer <destination>:0
Enter your password, and congratulations, you are running VNC via a secure shell connection.

If you have any questions, please send email to the admins.