Remote Desktop Protocol
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 Operating System and Mac OS X. The server listens by default on TCP port 3389. Microsoft refers to the official RDP client software as either Remote Desktop Connection (RDC) or Terminal Services Client (TSC).
Based on the ITU T.share protocol (also known as T.128), the first version of RDP (called version 4.0) was introduced with Terminal Services in Windows NT 4.0 Server, Terminal Server Edition. Version 5.0, introduced with Windows 2000 Server, added support for a number of features, including printing to local printers, and aimed to improve network bandwidth usage. Version 5.1, introduced with Windows XP Professional, included support for 24-bit color and sound. Version 5.2, introduced with Windows Server 2003, included support for console mode connections, a session directory, and local resource mapping. The most current version, 6.0, introduced with Windows Vista and Windows Server "Longhorn" includes a significant number of new features, most notably being able to remotely access a single application instead of the entire desktop, and support for 32-bit color.
Features
- 24-bit color support, giving a palette of 16.7 million colors. (8-, 15-, and 16-bit color are also supported.)
- 128-bit encryption, using the RC4 encryption algorithm (this is the default security; older clients may use encryption of lesser strength). But because of the man-in-the-middle vulnerability in the protocol and Microsoft's implementation, in many circumstances the traffic can be decrypted along the way.[1]
- Transport Layer Security support.
- Audio allows users to run an audio program on the remote desktop and have the sound redirected to their local computer.
- File System Redirection allows users to use their local files on a remote desktop within the terminal session.
- Printer Redirection allows users to use their local printer within the terminal session as they would with a locally or network shared printer.
- Port Redirection allows applications running within the terminal session to access local serial and parallel ports directly.
- The clipboard can be shared between the remote computer and the local computer.
Advantages
Clients compatible with the Remote Desktop Protocol run on a number of different operating systems, and it is even a core feature of some Linux distributions. Users do not, however, need a broadband connection to access their desktops, as even a 56K modem provides enough speed to provide 5-6 screen refreshes per second.
Supported Operating Systems
The RDP service is supported as an official feature on Windows Server 2003, Windows XP Professional, Media Center, and Tablet PC 2005 Editions, and in Windows Vista Ultimate, Enterprise and Business editions. While the software exists on other editions of Windows, including Windows XP Home Edition and Windows Vista Home Basic and Home Premium editions, as of March 2007, Microsoft hasn't announced any plans to sanction owners of those editions to enable Remote Desktop server capabilities on those versions. By default, all Windows XP and Vista editions include the Remote Desktop Connection (RDC) client application pre-installed, with RDC client version determined by the version of Windows release. It is available for free download for Windows Vista, Windows XP, Windows 2000, Windows 9x, Windows NT 4.0, Mac OS X, and most Linux distributions.
In early November 2006, Remote Desktop Connection 6.0 was released as a download exclusively for users of Windows XP Service Pack 2 or Windows Vista featuring the new Windows Vista visual theme and a number of other changes as listed below. The RDC 6.0 download requires Microsoft Windows Genuine Advantage validation.[2] Microsoft hasn't made any announcements confirming an update of RDC for other platforms, including the client for Mac OS X from its current version, 1.0.3, that would bring client-end features up to par with improvements of RDC 6.0.
Work has started on an open source implementation of the RDP server available for Unix-like operating systems.[3] There are other products which provide similar functionality for LINUX using non-RDP protocols such as VNC, NX and the X Window System. These are however not compatible with the Windows RDP client.
Default port and protocol
- Default port: 3389
- Protocol type: TCP
New Features in RDP 6.0
- Remote Programs: Application publishing with client-side file type associations.
- Seamless Windows: Remote applications can run on a client machine that is served by a Remote Desktop connection.
- Terminal Server Gateway: Enables the ability to use a front-end IIS server to accept connections for back-end Terminal Services servers via an HTTPS connection, similar to how RPC over HTTPS allows Outlook clients to connect to a back-end Exchange 2003 server.
- Support for remoting the Aero Glass Theme (or Composed Desktop), including ClearType font smoothing technology.
- Support for remoting of Windows Presentation Foundation applications: Compatible clients that have .NET Framework 3.0 support will be able to display full Windows Presentation Foundation effects on a local machine.
- Rewrite of device redirection to be more general-purpose, allowing a greater variety of devices to be accessed.
- All of Terminal Services will be fully configurable and scriptable via WMI.
- Improved bandwidth tuning for RDP clients.
- 32-bit Color Support
- Support for remote desktop sizes greater than 1600x1200.
- Support for Transport Level Security (TLS) 1.0 on both server and client ends (set as default).
References
See also
- Terminal Services
- Citrix MetaFrame
- Independent Computing Architecture
- X Window System
- Virtual Network Computing (VNC)
- NX technology
- rdesktop - free open source client for Unix platforms
- tsclient - free open source GUI frontend to rdesktop (Ubuntu, Gnome)
- VPN
External links
- Technical Overview of Terminal Services - a more detailed feature list.
- Remote Desktop Protocol - from Microsoft's Developer Network
- Understanding the Remote Desktop Protocol - from support.microsoft.com
- Remote Desktop Connection Client for Mac - Microsoft's free client for Mac OS X
- RDP 6 for Windows XP and Windows Server 2003
- Java RDP Client - Free Java Remote Desktop Connection Client
- Linux client (sourceforge.net)
- Linux client (website)