What Is Virtual Network Computing (VNC)?

Getting Connected with VNC (RealVNC)
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VNC (Virtual Network Computing) is a technology for remote desktop sharing, a form of remote access on computer networks. VNC enables the visual desktop display of one computer to be remotely viewed and controlled over a network connection.

Remote desktop technology like VNC is useful on home computer networks, allowing someone to access their desktops from another part of the house or while traveling. It is also useful for network administrators in business environments, such as Information Technology (IT) departments who need to remotely troubleshoot employees' systems.

VNC Applications

VNC was created as an open-source research project in the late 1990s. Several mainstream remote desktop solutions based on VNC were subsequently created. The original VNC development team produced a package called ​RealVNC. Other popular derivatives included UltraVNC and TightVNC. VNC supports all modern operating systems including Windows, MacOS, and Linux. For more, see our Top VNC Free Software Downloads.

How VNC Works

VNC works in a client/server model and uses a specialized network protocol called Remote Frame Buffer (RFB). VNC clients (sometimes called viewers) share user input (keystrokes, plus mouse movements and clicks or touch presses) with the server. VNC servers capture the local display framebuffer contents and share them back to the client, plus take care of translating the remote client input into local input.

Connections over RFB normally go to TCP port 5900 on the server.

Alternatives to VNC

VNC applications, however, are generally regarded as slower and offering fewer features and security options than newer alternatives.

Microsoft incorporated remote desktop functionality into its operating system starting with Windows XP. Windows Remote Desktop (WRD) enables a PC to receive remote connection requests from compatible clients. Besides client support built into other Windows devices, Apple iOS and Android tablet and smartphone devices can also function as Windows Remote Desktop clients (but not servers) via available apps.

Unlike VNC that uses its RFB protocol, WRD uses the Remote Desktop Protocol (RDP). RDP does not work directly with framebuffers like RFB. Instead, RDP breaks down a desktop screen into sets of instructions for generating the framebuffers and transmits only those instructions across the remote connection. The difference in protocols results in WRD sessions using less network bandwidth and being more responsive to user interaction than VNC sessions. However, it also means that WRD clients cannot see the actual display of the remote device but instead must work with their own separate user session.

Google developed Chrome Remote Desktop and its own Chromoting protocol to support Chrome OS devices similar to Windows Remote Desktop. Apple extended the RFB protocol with added security and usability features to create its own Apple Remote Desktop (ARD) solution for MacOS devices. An app of the same name enables iOS devices to function as remote clients. Numerous other third-party remote desktop applications have also been developed by independent software vendors.