Rdesktop

rdesktop is an implementation of a client software for Microsoft's proprietaryRemote Desktop Protocol (RDP). rdesktop is free and open-source software, subject to the requirements of the GNU General Public License (GPL-3.0-or-later), and is available for Linux and BSD as well as for Microsoft Windows.

As of August 2013, rdesktop implements a large subset of the RDP 5 protocol. Unlike Remote Desktop Connection in modern versions of Windows, rdesktop still supports the older RDP 4.0 protocol used by Windows NT 4.0 Terminal Server Edition and Windows 2000 Server.