RFB

RFB, or Remote Framebuffer, is a protocol used to remotely view and interact with the graphical desktop of another computer. It is the underlying protocol behind many VNC (Virtual Network Computing) implementations and is designed to be cross‑platform and relatively simple to implement.

In a typical RFB session, a client connects to a server, which owns a framebuffer representing the remote screen. The server sends updates to the client to refresh parts of the display, while the client sends input events such as keyboard presses and mouse actions back to the server. Updates are transmitted as rectangles of pixel data that can be encoded with various techniques to reduce bandwidth. Common encodings include Raw, CopyRect, RRE, Hextile, Tight, and ZRLE, with newer clients often supporting multiple options to balance quality and performance.

RFB supports a range of security options, and older implementations often transmitted data in plaintext. Modern deployments frequently use encryption via TLS or tunneling through SSH, and many VNC variants provide additional security layers or authentication methods. The protocol typically runs over TCP, with the default port 5900 followed by the display number (for example, 5901 for display 1).

History and ecosystem: RFB originated in the 1990s as part of the development of VNC and has since been standardized in several drafts and evolved through multiple implementations. Notable open-source and commercial clients and servers include TightVNC, TigerVNC, RealVNC, and UltraVNC, each supporting different encodings, security options, and performance optimizations. RFB remains widely used for remote administration, troubleshooting, and cross‑platform remote access.