Overview
VNC client software creates an image of a remote computer desktop on your PC or Mac, permitting you remote access to that computer with a Graphical User Interface (GUI).
Unix systems offer GUI interfaces (variously called X-Windows, GNOME, KDE, etc.) that are similar to the Microsoft
Windows or Apple Mac environments. On any of these systems (PC, Mac, or UNIX) commands are available from an command-line,
so one need not always use a graphical user interface (GUI).
However, most
people are more comfortable with a GUI than the command-line and the GUI will often make tedious jobs easy.
Using VNC, you will be able to use a UNIX GUI environment on a remote
computer as if you were sitting in front of that computer. In addition, if you need to perform long-running jobs, you can start
the job, then disconnect from the VNC session, and the job will
continue to run. Using an ssh (command-line) client, once you
log out, all programs you were running are shut-down. Using VNC,
you can then re-connect to your running session from any machine and view your desktop and jobs, just as
if you never logged out.
Establishing a VNC Session on the Workstation - The First Time
What's happening here?
Before you can use VNC, there are two (or three) steps you will need to
perform:
Step 1. Establish your first VNC environment and VNC session password.
- Passwords set in the Linux Cluster and on the Scientific Server have no relation to one another
- Your VNC password will remain the same unless you actively change it.
- The request to set a password will only be seen the first time
you use VNC.
- What's happing? Completing the password request creates a directory in your
account called '.vnc' which will contain your configuration information.
Unless you alter the files in that directory, you will never need to perform it again.
Step 2. Note and record your assigned a VNC Server Session window number.
A Server
Session is a desktop environment that runs on the UNIX computer even
after you log out. This allows you to connect to a running session from
anywhere remotely.
- That Server Session window number remains active unless you kill the session or the workstation or server is re-booted.
- Subsequent use of the same command will creates a new (and wasteful, confusing) VNC Server Session.
Step-by-step Instructions
Might you already have a VNC session running?
- If you are working in the Linux Cluster, check here to see if you already have a session running
- If you are working on the Scientific Server, look at the message that runs after you have logged in using SSH. That message describes any VNC sessions you have running.
- If you are already running a VNC session, skip to " Connecting to a VNC Session," below.
If not, request a VNC Session
1. From your PC or Mac, open a shell (SSH on PCs) to the computer (Linux workstation or Scientific Server) that you want to start
a session on. SSH is described here
2. At the command prompt, type in 'vncserver', and press
Enter.
3. If this is the first time you have started a VNC session, you will be prompted for a password to use for future VNC sessions. Selecting a VNC session password does not alter any other password you may now use, including the UNIX password. After
you have entered and verified your VNC session password, you a message describing the new session will be displayed and you will be returned to the
command prompt. Note this password and write it down; you will be using it repeatedy.
Note: You may wish to manage your VNC settings including the password. A separate page describes common (but usually only optional) VNC commands you could be interested in.
One of the first lines describing the new VNC session will read
New
'X' desktop is machine:y
where y is a number and machine is the name of the computer you have connected to. Note this number and write it down; you will be using it repeatedy.
4. Exit your SSH secure shell session by typing 'exit' and press
Enter.
Connecting to a VNC Session using a VNC Client:
What network are you connecting from? It makes a difference! If you are outside the University, y ou will need to "tunnel" your VNC client through a secure shell. Instructions for VNC tunneling are covered on another page. Please go there now, complete those operations, and then return to this point on this page.
5. If you have not done so before, download and install a VNC client.
6. Run VNC viewer from the start menu or an icon you may have placed on your desktop.
7. In the connection details dialog, what you enter depends on whether you are connecting from within the University network or tunneling into it using Secure Shell.
Connecting a VNC session
| From Within The University |
Through SSH Tunneling
If you are outside the University, you will need to "tunnel" your VNC clit through a secure shell. Instructions for VNC tunneling are covered on another page. Please go there now, complete those operations, and then return to this point on this page. |
machine.umdnj.edu:y
Based on the example of the workstation named carbon and having been assigned window 2, the address would be carbon.umdnj.edu:2
Type that address into the dialog box...
..then press 'OK'. |
127.0.0.1:y
Based on our example of having been assigned window 2, the address would be 127.0.0.1:2
Unlike connecting directly within the university, you selected your machine when you set up your SSH tunnel profile.
Type that address into the dialog box...
..then press 'OK'.
|
8. In the VNC Authentication dialog,
enter the password you supplied from "Running VNC Server for the First Time" above.
You should now see your desktop appear in a window. It
should look something like this:
When you wish to disconnect from your session, simply close the window.
If you want to kill or shut-down your running VNC server session, see the instructions
here. Generally, you will only want to shut down the window. That leaves your desktop ready to resume work where you stopped. In addition, any programs you are running will continue to run, often completing your project while you do something else.
Page Last Updated May 9, 2007
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