The Microsoft Remote Desktop Protocol (RDP) provides remote display and input capabilities over network connections for Windows-based applications running on a server. Using RDP, clients can access the desktop and other facilities (e.g., file shares) of remote computers. The proxy currently supports two versions of the RDP protocol: RDP4 and RDP5. RDP4 uses 512bit RSA keys to encrypt the communication, and does not support the forwarding of additional facilities. RDP5 uses either 512bit RSA keys (RDP4-style) or X.509 certificates (RDP5-style) for encryption, and can forward additional facilities like disk shares or sound.

Both versions support specifying a default username and optionally a password for it.