Remote Desktop Protocol (RDP) is a proprietary protocol developed by Microsoft, which provides a user with a graphical interface to connect to another computer over a network connection. The user employs RDP client software/service for this purpose, while the other computer must run RDP server software /service.
The RDP servers could be Windows Server( Server 2019, 2019, 2012 ), a Windows PC. (Windows Home version doesn’t come with the RDP feature.) and Linux Servers(Ubuntu, CentOS, RedHat etc.).
By default, the server listens on TCP port 3389 and UDP port 3389.