Remote Desktop Protocol (RDP) is a multi-channel protocol that allows a user to connect to a computer running Microsoft Terminal Services. Clients exist for most versions of Windows (including handheld versions), and other operating systems such as Linux, FreeBSD, Solaris and Mac OS X. The server listens by default on TCP port 3389.[1] Microsoft refers to the official RDP client software as either Remote Desktop Connection (RDC) or Terminal Services Client (TSC).