VNC is an open source remote control program written by AT&T's Lab in Cambridge. I might have the banners up to their sites, but I didn't write it. VNC comprises of two main components: the viewer and the server. The server takes incoming connections over TCP/IP and sends back a user desktop to the viewer. The viewer is a smallish file, although many versions of VNC support the use of a browser instead.

The only completely secure computer is one without a network. If a computer does have a network connection, then it is only as secure as its weakest point, whether this be the level of network encryption supported, the quality of users' passwords, or the internal security of the server computer. VNC Enterprise and Personal Editions include support for strong encryption and authentication of VNC connections.

VNC requires TCP/IP network connectivity between the viewer and server computers. A simple test is to use the ping utility. If you can't ping from your viewer to your server, and vice-versa, than VNC will not work!

We find VNC to be perfectly acceptable as our normal method of accessing Unix desktops on a daily basis. This is over a 10 Mbit/s ethernet on reasonably modern machines, using the X or Win32 viewer. Because Windows gives us fewer hints about what it's doing, and because we don't have the source code for Windows in the same way that we do for X, the WinVNC server has to work harder to find out what's changed, and so a really fast machine should make a big speed difference.

Many organizations operate firewalls to reduce the risk of intrusion by malicious attackers via the Internet. These firewalls typically operate by only allowing connections in to machines in that organization on specific ports. Which ports are permitted access depends upon the network protocol that uses the port and the degree of security it provides.

We find VNC to be perfectly acceptable as our normal method of accessing Unix desktops on a daily basis. This is over a 10 Mbit/s ethernet on reasonably modern machines, using the X or Win32 viewer. Because Windows gives us fewer hints about what it's doing, and because we don't have the source code for Windows in the same way that we do for X, the WinVNC server has to work harder to find out what's changed, and so a really fast machine should make a big speed difference.

Access to your VNC desktop generally allows access to your whole environment, so security is obviously important. VNC uses a challenge-response password scheme to make the initial connection, but after that the data is unencrypted and could, in theory, be watched by other malicious users, though it's a bit harder to snoop a VNC session than, say, a telnet, rlogin, or X session.

VNC automatically adapts to the available bandwidth, for example by using a lower colour level and greater compression over slower network connections, as well as sending updates only as quickly as the available network bandwidth allows. How much bandwidth VNC uses therefore depends upon the frame-rate & colour level required, and the activity being performed.

How do I use VNC through my NAT router? (AKA Why do I get Connection timed out/Connection refused errors?)

You should run the vncserver script to start a VNC server, rather than the Xvnc program directly. vncserver runs Xvnc with appropriate options and starts some X applications to be displayed in the VNC desktop. The applications it tries to start are specified in $HOME/.vnc/xstartup, which can be tailored to your requirements. The default setup is to run the 'twm' window manager and a single 'xterm' window. If these applications fail to run, then you will see a grey 'rootweave' desktop.

It depends on your firewall, and whether you want to access a server inside your firewall from elsewhere, or a server outside your firewall from inside. Generally firewalls are designed to prevent incoming connections except to certain well-known machines and ports. If you can configure these to include your VNC server, then you will be able to access it from anywhere in the world.

The first step is to download and install the VNC server extension (vnc4x-x.x.x.dsl) from the repository. There are two options for starting VNC automatically. You can place the commands in /opt/bootlocal.sh or in /home/dsl/.xinitrc, a hidden file in /home/dsl. You can find the two commands you need in the /home/dsl/.fluxbox/menu file. If you place these files in the .xinitrc file they MUST be before the fluxbox entry and have the '&' sigh following each command to run it in the background.

Why VNC? VNC is a remote display protocol that works well over slower connections. It will let you run graphical programs such as Matlab and Maple remotely in a virtual session. In addition, this session will continue to run until explicitly terminated. You use a VNC viewer to connect to the session and control it but you can disconnect at any time and return later. Initial Setup First, connect via SSH to the machine you want to run your VNC session on, cauchy.math.duke.

Louis Joyce wrote in and offered the following command line: for /f "tokens=1" %i in (workstations.txt) do call vnc %i /reg /config d:\fplocation\pass.ini You can use the NT resource kit tool GLOBAL to get a list of computers by reading the members of domain computers. Failing that, you need to write a quick vbscript. :-) Because the script uses special net use commands, you can't run it from Windows 95, 98 or ME. It only works on NT, 2000 and XP.

We find VNC to be perfectly acceptable as our normal method of accessing Unix desktops on a daily basis. This is over a 10 M/bit ethernet on reasonably modern machines, using the X or Win32 viewer. Because Windows gives us fewer hints about what it's doing, and because we don't have the source code for Windows, the NT server has to work harder to find out what's changed, and so a really fast machine should make a big speed difference.

The binary files for each supported distribution are located in c:\fastpush\vnc7. Each folder under there represents a distribution of VNC. Simply download the latest binaries from the owners of each distribution and replace the files in the respective folders.

No, not at present in the standard versions. However, it is possible to stop the user closing the VNC Server or changing the VNC Server settings. Please refer to the documentation.

Yes. VNC Server for Windows Configuration allows the port numbers for VNC connections and for serving the Java Viewer to be configured. See the Connections Options section of the appropriate documentation. In Unix, you can specify it on the Xvnc or vncserver command-line.

No. The VNC binaries we distribute are virus-checked before release, and are also signed on platforms that support signed binaries. VNC does not include nor install adware nor spyware of any kind. The most likely cause of VNC being detected as a virus, adware or spyware is that your computer has become infected with a virus that attaches itself to existing files.

The short answer is: You can't! However, when the classic VNC Authentication scheme is used to authentication the user, only the first eight characters of the user's password are checked. This means that the passwords "01234567hello" and "01234567world", for example, would be regarded by VNC Server as identical. This is a limitation only when using VNC Free Edition or older VNC software.

There are a couple of possible causes of problems authenticating yourself to the VNC Server. The most basic of these is that you have not configured a VNC Authentication password - VNC Server won't let you connect without supplying a password unless the server is explicitly configured to use No Authentication. If you have previously used VNC Free Edition, and have upgraded to a secure version, you may find that VNC Server rejects your password if it is longer than eight characters.

By default the VNC server will accept connections on TCP port 5901. Under the Linux environment, you can start multiple sessions at once, so the number will increase with each VNC session, i.e. 5901, 5902, 5903, etc...