Remote Desktop Protocol (RDP) is a secure network communications protocol for Windows-based applications running on a server.
RDP allows network administrators to remotely diagnose and resolve problems encountered by individual subscribers. RDP is available for most versions of the Windows operating system as well as Mac OS X. An open source version is also available.
Noteworthy properties of RDP include encryption, smart card authentication, bandwidth reduction, resource sharing, the ability to use multiple displays and the ability to disconnect temporarily without logging off. RDP also allows redirection of functions such as audio and printing.
RDP can support up to 64,000 independent channels for data transmission. Data can be encrypted using 128-bit keys and the bandwidth reduction feature optimizes the data transfer rate in low-speed connections.
The protocol has presented some security issues, however. For instance, if an administrator opens a thin-client connection between computers, an attacker who is able to break into the RDP connection would have administrator privileges on both computers. It is generally recommended that RDP only be used when it is absolutely necessary and that both the administrator and end user run with the lowest level of privileges possible.