VNC Applications
VNC was created as an open-source research project in the late 1990s. Several mainstream remote desktop solutions based on VNC subsequently emerged. The original VNC development team produced a package called RealVNC. Other popular derivatives included UltraVNC and TightVNC. VNC supports all modern operating systems.
How VNC Works
VNC works in a client/server model and uses a specialized network protocol called remote frame buffer. VNC clients (sometimes called viewers) share user input—keystrokes, mouse movements, clicks, and touches—with the server. VNC servers capture the local display framebuffer contents and share them back to the client, which then translates 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 offer fewer features and security options than newer alternatives. Microsoft incorporated remote desktop functionality into its operating system starting with Windows XP. Windows Remote Desktop enables a Windows computer to receive remote connection requests from compatible clients. Besides client support built into other Windows devices, iOS and Android tablet and smartphone devices also can function as Windows Remote Desktop clients (but not servers) using available apps. Unlike VNC that uses its RFB protocol, WRD uses the remote desktop protocol. RDP does not work directly with framebuffers as RFB does. Instead, RDP breaks down a desktop screen into sets of instructions to generate 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. That also means, however, 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 solution for macOS devices. An app of the same name enables iOS devices to function as remote clients. Independent software vendors have developed numerous other third-party remote desktop applications as well.
