and be far away? Work with WINDOWS or a Mac under Linux? Every PC is able
to be steered by any other? You think this is a dream every administrator
of heterogeneous networks does have?
With VNC (Virtual Network Computing) you
are able to remote control another PC inside a network. You see the same
desktop as if you were sitting in front of it. This does not just work
between Linux machines but also between WINDOWS and any other combination
of WINDOWS, Linux and MacOs computers.
VNC own two programs, the viewer (vncviewer) and the server (vncserver). The server has to be started on the computer that you want to access and the viewer on the PC where you want to work at. If you want to administrate the computers inside the network all over you need the server and viewer for the different platforms. The viewer is also available as a Java version and you just need a web browser that supports it. Until now you have been able to use VNC with the following operation systems:
If you use a SUSE system you should install the included rpm package vnc.rpm . Other distribution have to download the source or the pre compiled versions if it is not included. You get the necessary packages at http://www.uk.research.att.com/vnc/ download.html. After installing the software you start at server with
>> vncserverTo increase the security you should never start the server as root only as a normal user. Later you can get root access via su in a xterm.
During the first starting of vncserver a password is wanted that restricts any access later. The server is started as a deamon and needs few CPU power.
Linux supports more than one X-server. Does already one X-server run it gets the ID "localhost:1", in this case the vncserver starts a new X-server using ":2" if this number is free. The standard output prompts the following message:
"New 'X' desktop is paul:2"You need this port number to build a connection with vncviewer to the server. As a first try you should start vncviewer at the same computer as the server runs
>> vncviewer localhost:2and the number corresponds to the port that was activated with vncserver.
Now it asks for the password and then a window opens. In this one a usual X-server appears with a windowmanager (default twm) and a terminal. The configuration which program are started is set in the file ~/.vnc/xstartup . These programs are started after logging in with vncviewer. The last entry start the windowmanager. If you own a slow network connection you should keep it as it is. If you still have free resources you could choose a bigger on like WindowMaker or KDE.
On WINDOWS the installation runs as usually.
After downloading and decompression the files you are able to use the viewer
at once without any installation procedure. The vncserver has to be installed
At Linux you should not start the vncserver
automatically during booting because any access to the Linux PC is then
just saved by this vnc password. It is much safer to start the server on
the Linux PC by your own logging in from outside (if possible with secure
shell, ssh) and stop it after closing the viewer at the end of the session.
It is recommended to use different passwords for vnc and your normal login.
X-Windows (XFree86) has been designed and
optimized to be used inside networks from the beginning of its development
and needs few network resources. WINDOWS was not designed to produce low
traffic and the vncserver works very hard to submit all data to the Linux
PC. That is why the window handling is quite slow. If you control a Linux
session from WINDOWS you will see it is much faster. In addition it is
possible to use more than one X-server and many people can work on one
computer at the same time.
The greatest independence of VNC was reached as they presented a java version. Since then it has been possible to remote control from any OS. The only thing that is needed is a web browser that supports Java. Instead of the vncviewer the browser contacts the server. Just enter the site http://IP_Number:5801 . The IP number chooses the PC where the server runs and the last port number corresponds to the X-server that was started. A very fast computer is recommended because the screen display happens with Java and takes much CPU resources. You are able to accelerate the presentation if you do not use a pixmap in the background just a one color windowmanager. You reach this with the command
>> xsetroot -solid white