What Is Virtual Network Computing VNC?

Virtual network computing facilitates remote desktop sharing, a form of remote access on computer networks. VNC displays the visual desktop display of another computer and control that computer over a network connection. Remote desktop technology like VNC runs across home computer networks to access a computer from another part of the house or while traveling. It is also useful for network administrators in business environments such as information technology departments who need to remotely troubleshoot systems.

VNC works in a client/server model and uses a specialized network protocol called the remote frame buffer. VNC clients (sometimes called viewers) share user input keystrokes, mouse movements, clicks, and touches with the server. Virtual network computing (VNC) is a type of remote-control software that makes it possible to control another computer over a network connection. Keystrokes and mouse clicks are transmitted from one computer to another, allowing technical support staff to manage a desktop, server, or another networked device without being in the same physical location.

VNC works on a client/server model A VNC viewer (or client) is installed on the local computer and connects to the server component, which must be installed on the remote computer. The server transmits a duplicate of the remote computer's display screen to the viewer. It also interprets commands coming from the viewer and carries them out on the remote computer.VNC is platform-independent and is compatible with any operating system. Computers must be networked with TCP/IP and have open ports allowing traffic from the IP addresses of devices that may need to connect.VNC was developed at AT&T Laboratories. The original VNC source code is open source under the GNU General Public License, and other variations are also available commercially.

In computing, Virtual Network Computing (VNC) is a graphical desktop sharing system that uses the Remote Frame Buffer protocol (RFB) to remotely control another computer. It transmits the keyboard and mouse events from one computer to another, relaying the graphical-screen updates back in the other direction, over a network.VNC is platform-independent – there are clients and servers for many GUI-based operating systems and for Java. Multiple clients may connect to a VNC server at the same time. Popular uses for this technology include remote technical support and accessing files on one's work computer from one's home computer, or vice versa.VNC was originally developed at the Olivetti & Oracle Research Lab in Cambridge, United Kingdom. The original VNC source code and many modern derivatives are open sources under the GNU General Public License.

There are a number of variants of VNC which offer their own particular functionality; e.g., some optimized for Microsoft Windows or offering file transfer (not part of VNC proper), etc. Many are compatible (without their added features) with VNC proper in the sense that a viewer of one flavor can connect with a server of another; others are based on VNC code but not compatible with standard VNC.

RFB ("remote framebuffer") is an open simple protocol for remote access to graphical user interfaces. Because it works at the framebuffer level it is applicable to all windowing systems and applications, including Microsoft Windows, macOS, and the X Window System. RFB is the protocol used in Virtual Network Computing (VNC) and its derivatives.

By default, a viewer/client uses TCP port 5900 to connect to a server (or 5800 for browser access), but can also be set to use any other port. Alternatively, a server can connect to a viewer in "listening mode" (by default on port 5500). One advantage of listening mode is that the server-side does not have to configure its firewall/NAT to allow access on the specified ports; the burden is on the viewer, which is useful if the server site has no computer expertise, while the viewer user would be expected to be more knowledgeable.

Although RFB started as a relatively simple protocol, it has been enhanced with additional features (such as file transfers) and more sophisticated compression and security techniques as it has developed. To maintain seamless cross-compatibility between the many different VNC client and server implementations, the clients and servers negotiate a connection using the best RFB version, and the most appropriate compression and security options that they can both support.

RFB was originally developed at Olivetti Research Laboratory (ORL) as a remote display technology to be used by a simple thin client with ATM connectivity called a Video tile. In order to keep the device as simple as possible, RFB was developed and used in preference to any of the existing remote display technologies.

RFB found a second and more enduring use when VNC was developed. VNC was released as open-source software and the RFB specification published on the web. Since then RFB has been a free protocol that anybody can use. When ORL was closed in 2002 some of the key people behind VNC and RFB formed RealVNC, Ltd.in order to continue the development of VNC and to maintain the RFB protocol.