Virtual Network Computing (VNC)
technology enables sharing a copy of one computer's screen display with another computer over a network connection. Also known as remote desktop sharing
, VNC is typically used by people wanting to monitor or control a computer from a remote location rather than just accessing shared files.
The following free software packages provide VNC functionality. VNC software consists of a client user interface plus a server that manages connections to clients and sends desktop images. Some applications only support Windows PCs, while others are portable across different types of network devices.
VNC systems use network authentication to guard the connections initiated between clients and a server, but the remote desktop data subsequently sent over these connections is usually not encrypted. Those wanting to also protect the data can use free SSH utilities together with a VNC system.
The TightVNC Server and Viewer use special data encoding techniques designed to better support lower-speed network connections. First released in 2001, the latest versions of TightVNC run on all modern flavors of Windows, and a Java version of the Viewer is also available.
The creation of TigerVNC software was initiated by Red Hat with the goal of improving on TightVNC. TigerVNC development started from a snapshot of TightVNC code and has expanded support to include Linux and Mac as well as Windows, plus various performance and security enhancements.
The company RealVNC sells commercial versions of its VNC products (Personal Edition and Enterprise Edition) but also supplies this open-source Free Edition. This free client is not officially supported on Windows 7 or Vista PCs, but workaround procedures might allow it to function. RealVNC also sells (but not does provide a free version of) its VNC Viewer for iPhone and iPad on the Apple app store.
Developed by a small team of volunteers, UltraVNC is an open source VNC system that works similarly to RealVNC but supports Windows 7 and Vista clients. A companion software package called ChunkVNC
adds remote control functionality to the UltraVNC viewer.
Based on an older software package called Chicken of the VNC, Chicken is an open source VNC client for Mac OS X. The Chicken package does not include any VNC server functionality, nor does the client run on any other operating system than Mac OS X. Chicken can be paired with various VNC servers including UltraVNC.
JollysFastVNC is a shareware VNC client for Mac created by software developer Patrick Stein. While the developer strongly encourages regular users to purchase a license, the software is free to try. JollysFastVNC is designed for speed (responsiveness) of remote desktop sessions and also integrates SSH tunneling support for security.
SmartCode Solutions provides this hosted Web page demonstrating how a browser running their ViewerX client software can be used as a VNC client. The SmartCode ViewerX products are not free, but this demonstration client can be used freely from Windows PCs using an ActiveX-control enabled browser like Internet Explorer.
Mochasoft provides both a full commercial (pay, not free) version and this free Lite version of its VNC client for Apple iPhone and iPad. Compared to the full version, Mocha VNC Lite lacks support for special key sequences (like Ctrl-Alt-Del) and some mouse functions (like right-click or click-and-drag). The company has tested this client with various VNC servers including RealVNC, TightVNC and UltraVNC.
Echoagent Systems designed EchoVNC to be a "firewall friendly" remote desktop package based on UltraVNC. However, the extensions in EchoVNC for improved firewall compatibility rely on a proxy server system called "echoServer" that is a separate, commercial product.