Virtual Network Computing

Virtual Network Computing, VNC, is a software that displays the screen content of a remote computer (server) on a local computer (client) and sends keyboard and mouse movements on the local machine to the remote computer in return. So you can work on a remote computer as if you were sitting right in front of it. VNC implements the Remote Frame Buffer Protocol and is thus, in contrast to other remote control software, platform independent usable.

Historical background

VNC was developed in the Olivetti Research Laboratory ( ORL). In 1999, the laboratory of AT & T was bought and closed in 2002.

A number of developers who also worked on VNC at AT & T Research Lab, among others, the inventor Tristan Richardson, the project manager Andy Harter and Quentin Stafford - Fraser, James Weatherall, Ken Wood, Andy Hopper, Charles McLachlan, Paul Webster and Hendrik Ekkelenkamp.

After the laboratory was closed in 2002, several members of the development team, including Richardson, Harter, Weatherall and Hopper, the company RealVNC established to continue work on VNC. It featured a scaled-down open- source version under the GNU General Public License has already been at that time in addition to commercial VNC versions published.

In this way, different Forks, which contain various improvements and additional features that are all but largely compatible with the original version developed. The Remote Frame Buffer protocol used is understood by all in version 3.3 VNC versions and now serves as a " lowest common denominator " when using various VNC programs.

Meanwhile, there are VNC implementations for all major operating systems, so VNC is considered as platform independent.

Operation

VNC operates on the client-server model. The server program runs on the computer, its screen output to be monitored, whereas the client programs receive the screen output and in turn can send keyboard and mouse input to the server.

Newer versions of VNC have is that they also provide the functionality together mostly to the VNC server itself one equipped with minimal functional Web server that provides a Java applet, so that access even without installed VNC client software on any Java - capable browser is possible.

Privacy Policy

With VNC example, it is possible that the administrator of a network, the control of the computer of an employee accepts to install or troubleshoot software. However, VNC can be abused as a spy software. Many implementations allow an unobtrusive to the user of the monitored computer use. To the same extent may also be secured by the use VNC software but: How is the Windows version of the RealVNC server in the taskbar with a white icon indicates that the server is running. This turns black as soon as a viewer connects to the server, so that the user of the computer on which the server is running, the remarkably. Many implementations also provide the ability to query passwords on connect (not provided in the RFP- Standard) or to obtain a consent from the user of the monitored computer to establish a connection in a dialog box displayed on the computer to be monitored. Alternatively, it is also a plain "read" mode is possible in which so have local input when viewer no effect on the remote VNC server machine.

Since the Remote Frame Buffer protocol is unencrypted, all the keystrokes of the viewer are sent unencrypted over the network on principle. When you enter sensitive information (such as passwords), therefore, as with any other network protocol, the risk of spying out the data.

Known implementations

The best known VNC programs that have both client and server are:

  • RealVNC is the "official" development of the AT & T VNC and is licensed under the GNU General Public License. However, only the very circumcised " Free Edition " is free.
  • TightVNC: A VNC server and client under the GPL license, available for Windows and many Unix derivatives such as Linux; In addition, there is a platform independent implementation in Java (client only ), which must not be installed. TightVNC is an extensive development of the VNC program, particularly noteworthy are the compression options to allow VNC problems even on low bandwidth ( " Tight" encoding). The program can transfer encrypted passwords only, the data transfer itself is not encrypted.
  • UltraVNC: A VNC server and client for Windows under the GPL. It offers additional features such as file transfer, chat and Mirror Video Driver for very short transmission intervals for broadband ( such as DSL or a local network), as well as the " Tight" encoding TightVNC. With UltraVNC authentication is possible not only through the regular password encryption, but also about the Microsoft Logon authentication method I and II, which find their application in the NT domain concept, and Microsoft directory service. For the encryption of the data stream between the server and client of external UltraVNC DSM plugin modules are used. The DSM plugin modules enable RC4 or AES encryption to a key length of 128 bits.
  • X11vnc - directs X-Window displays real (physical screen, keyboard and mouse ) to any VNC client on. With built-in SSL encryption and authentication, UNIX user and password support, and file transfer with TightVNC and UltraVNC. In addition, extended for webcams, TV tuner and embedded Linux systems. Additional Enhanced TightVNC viewer for Unix and Windows. GPL license.
  • LibVNCServer / LibVNCClient are cross-platform C libraries which can be used, which make it possible to integrate VNC server or VNC client functionality into your own applications. GPL license.
  • Contiki VNC server as CTK- topic ( Contiki Toolkit)
  • Krdc and krfb - Client and server for KDE.
  • Vino - Client and server for GNOME.
  • CSpace - encrypted done remote control for Windows computers via VNC, free, open source, authentication and communication, it will be when installing RSA key pairs with 2048 -bit public key generated and stored on a central server.
  • Directvnc is a VNC client for framebuffer issues. He uses DirectFB and therefore does not require an X server. This makes it suitable for very low-power Unix systems.
  • Chicken of The VNC: VNC client for Mac OS X ( GPL)
  • JollysFastVNC: VNC client for Mac OS X
  • VineServer (formerly OSXvnc ): VNC server for Mac OS X ( GPL)
  • OS9vnc: VNC server for Mac OS 9 and Mac OS 8
  • PalmVNC: VNC client for Palm devices
  • Apple Remote Desktop: VNC client for Mac OS X
  • Mocha VNC Lite: Does VNC possible as an application for iPod touch and iPhone. Compatible with PC and Macintosh.
  • Portable VNC: VNC Viewer for Sony PSP
  • MVNC: VNC server for Symbian S60 phones
  • VNsea: VNC Viewer for the Apple iPhone
  • TouchpadPro: VNC Viewer for the Apple iPhone based on VNsea
  • TigerVNC: elimination of TightVNC
  • EfonVNC. VNC server for Windows CE NET (4.x ), Windows CE 5.0 and Windows Embedded CE 6.0. License: GPL.
  • PocketVNC: VNC server and HTML5 Viewer for Windows Mobile, Windows CE 4.x, Windows CE 5.0 and Windows CE 6.0.

Xvnc

Xvnc is software based on a standard X - server. Instead of a real, physical desktops uses Xvnc doing a virtual desktop. X applications are thereby shown on a normal X server, but can be displayed and operated via a VNC viewer.

Xvnc represents two different servers: one for the X server, where the default window manager (eg GNOME or KDE ) is started, on the other hand a VNC server that can be accessed through the client. Due to the technology of the UNIX X server, it is possible to start multiple instances of Xvnc on a computer.

The VNC server is not normally run directly on Xvnc, vncserver but using the supplied Perl script.

Xvnc is an integral part of almost all applications running on UNIX systems VNC servers.

VNC as a multi- screen operation

Thanks to its enormous popularity, the VNC protocol is being used increasingly to simulate multi-head capable graphics cards. These running a computer with a special " multi-monitor software" usually a virtual VNC server provides. From the second computer, the monitor you want to use as an extension to the First, put them ordinary VNC client to connect to the virtual VNC server. Shown is then not monitor the content of the other, but the corresponding simulated virtual extension part.

Known proprietary " multi-monitor applications " are ScreenRecycler for Apple Macintosh ( Shareware ) and ZoneScreen ( freeware ) and Maxi Vista for Microsoft Windows.

Electronic visual display Client (computing) RFB protocol Remote administration Paul Webster (producer) Java-Applet Advanced Encryption Standard Transport Layer Security Embedded system Vino (VNC server) Palm, Inc. S60 (software platform)
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