It is a proprietary protocol developed by Microsoft, and the standard remote desktop protocol used in Windows operating systems. With RDP you can connect to a remote computer over the Internet, to access the computer’s files and programs as if you were using its own keyboard, display screen and mouse. xRDP works with rdesktop, FreeRDP, NeutrinoRDP and Windows RDP. It enables the non-Windows operations systems like Linux and BSD to provide an RDP-compatible remote desktop experience.
XRDP is a free and open-source implementation of the Microsoft RDP (Remote Desktop Protocol) server.