What Is Terminal Services?

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

What Is Terminal Services?

In this section

  • Reducing the Total Cost of Ownership

  • Common Terminal Services Scenarios

  • Interactions with Other Technologies

  • Related Information

Terminal Services provides the ability to host multiple, simultaneous client sessions on Windows Server 2003. Terminal Services is capable of directly hosting compatible multi-user client desktops running on a variety of Windows-based and non Windows-based computers. Standard Windows-based applications do not need modification to run on the terminal server, and all standard Windows Server 2003-?based management infrastructure and technologies can be used to manage the client desktops. In this way, corporations can take advantage of the rich choice of applications and tools offered by today’s Windows operating system environment.

Reducing the Total Cost of Ownership

Organizations are always searching for ways to reduce the costs of ownership and this is one of the major goals of Terminal Services. Terminal Services lets enterprises more easily and cost-efficiently accomplish this goal by allowing organizations to:

  • Centrally deploy and manage Windows-based applications.

  • Remotely administer Windows Server 2003-based computers.

Centrally deploy and manage Windows-based applications.

Terminal Services provides centralized deployment and management of 32-bit Windows-based applications to Windows-based terminals, remote users, or local PC desktops. Using Terminal Services, companies can ensure that all clients are using the current version of an application because the software is installed once on a server computer, rather than on every desktop throughout the company. This model reduces the costs and challenge of updating desktop machines, especially for remotely located desktops or branch office environments. In addition, Terminal Services features such as Remote Control can simplify application support.

Organizations can use Terminal Server mode to deliver Windows-based applications to heterogeneous desktop environments, over local area network (LAN), wide area network (WAN) and dial-up connections. This is a cost-effective way to deploy line-of-business applications that are frequently updated, hard to install, or need to be accessed over low-bandwidth connections.

Terminal Services acts as a convenient bridging tool for earlier desktops migrating to Windows XP Professional. It allows the Windows XP desktop experience to be delivered “virtually” to non-PC desktops and PCs that need hardware upgrades before they can run a full Windows XP operating system locally. Terminal Services clients are available for many different desktop platforms including Microsoft MS-DOS, Windows-based PCs, Macintosh, UNIX and others. By letting users access current applications on hardware that might otherwise be of little use, Terminal Services can help companies that are gradually replacing older machines. (Connectivity to MS-DOS, Macintosh, and UNIX-based machines requires a third party add-on such as Citrix MetaFrame).

Remotely administer Windows Server 2003-based computers

Remote Desktop for Administration can greatly reduce the overhead associated with remote administration. Enabled by Terminal Services technology, Remote Desktop for Administration is specifically designed for server management. Therefore, it does not install the application-sharing and multi-user capabilities or the process scheduling of the full Terminal Server component (formerly called Terminal Services in Application Server mode). As a result, Remote Desktop for Administration can be used on an already busy server without noticeably affecting performance and CPU utilization, which makes it a convenient and efficient service for remote management.

Remote Desktop for Administration is used to remotely manage Windows Server 2003 servers. This mode is designed to provide operators and administrators with remote access to typical back-end servers and domain controllers. The administrator has access to the graphical user interface-based tools that are available in the Windows environment, even if he or she is not using a Windows-based computer to administer the server. Administrators can securely manage their Windows Server 2003-based computers over any network connection from any device using the Terminal Services Client software. This lets an administrator perform tasks such as directory maintenance, virus scans, backups, reboots and even promote a server to be a domain controller—all from a remote location.

Remote Desktop for Administration allows for the management of servers from any location without affecting server performance or application compatibility. In addition to the console session, up to two remote administration sessions are supported; since this is meant as a single-user remote access solution, no Terminal Server Client Access License (CAL) is required to use Remote Desktop for Administration.

Administrators can also fully administer computers running Windows Server 2003 family operating systems from computers running earlier versions of Windows by installing Remote Desktop Connection.


  • Remote Desktop for Administration is disabled by default in Windows Server 2003 family operating systems.

Common Terminal Services Scenarios

The way in which you plan to use Terminal Server has an effect on how you deploy it. The following scenarios outline the various ways in which you might use Terminal Server in your organization. Use the information in these scenarios to clarify how you are going to use Terminal Server in your organization.

Hosting Line-of-Business Applications

If your organization or certain groups within your organization use specialized applications to do their work, it might be beneficial to host the applications with Terminal Server. For example, you might decide to use Terminal Server in the following situations:

  • Custom applications. If your line-of-business application is developed in-house or especially for your organization, and it tends to require frequent updating or repair, deploying the application once on a terminal server can simplify administration of the application. This is especially useful if your environment is geographically dispersed or if you are deploying Terminal Server to centrally serve your organization’s branch offices.

  • Large central data pool. Applications that rely on access to a single data source often run better on a terminal server because large amounts of data do not have to travel across the network to users. Instead, the data processing takes place on the server. Only the keystrokes and display information travel across the network, so you can use lower bandwidth connections. This is especially useful if the users of the data pool are located remotely, for example in a branch office with a slow connection to the database server.

  • Task workers. In environments where you want workers to access only the application that they need to perform their jobs, you can centralize the administration of these users by using Terminal Server.

  • IT Admin tools. System administrators can perform tasks that require Enterprise Administrator or Domain Administrator permissions on a terminal server that has the necessary tools installed on it. They can also run their desktop applications on their local computer without these permissions.

  • Upgrading operating systems. If your organization uses a line-of-business application that is not optimized for your desktop operating system, you can host the application with Terminal Server rather than change operating systems.

Hosting the Desktop

You can use Terminal Server to host user’s entire desktop environments, so that when users log on, they see their usual desktop environments or desktop environments especially designed for their remote use. In this situation, users can open and close the applications they choose in the same way that they access applications from the Windows desktop on the local computer. You can host the desktop in the situations discussed in the following sections.

Remote users

Hosting the desktop with Terminal Server can provide consistency and better performance for users in remote locations because large amounts of application data are not being transmitted over the connection. For example, you might use Terminal Server in the following situations:

  • Bandwidth-constrained locations. In areas where high bandwidth is not available or cost-effective, deploying applications on a terminal server can improve performance for users who are connecting to the network from a remote location.

  • Mobile users. For users who are traveling and tend to access the corporate network over connections of varying bandwidth, Terminal Server can provide a more consistent experience.

Client heterogeneity

If your organization is in the process of converting all users to the same platform or upgrading desktop hardware, you can use Terminal Server to quickly deliver the most up-to-date version of the operating system and applications to the user while enabling you to spread the desktop platform or hardware conversion over a longer period of time. You can also deliver a highly controlled standard desktop to users by using Terminal Server, as illustrated in more detail in the following list:

  • Mixed-platform environment. If you have users who require applications based on operating systems other than Windows to perform their jobs, but your organization is transitioning to or requires a Windows-based desktop, you can host the desktop with Terminal Server. This requires the use of third-party software in conjunction with Terminal Server.

  • Upgrading hardware. If your organization is planning to upgrade to Windows XP on the desktop, but not all of the desktop hardware is compatible, you can use Terminal Server to host the desktops of users who have older hardware while you are in the process of upgrading the hardware. All users can have the same desktop environment and run the latest versions of the applications designed for Windows XP regardless of their desktop hardware.

  • Highly controlled environments. In situations where you want to deliver a standardized and controlled environment to users, you can host the desktop with Terminal Server to centralize management.

Hardware Considerations

You can reduce hardware costs by hosting applications with Terminal Server and using thin client devices or older hardware on your user’s desktops.

  • Use of thin clients. Windows Powered thin clients (sometimes called Windows-based terminals) offer an alternative to personal computers and traditional “green screen” terminals by enabling easy remote access to productivity and line-of-business applications that are hosted on Windows-based terminal servers.

  • Extending the life of older hardware. Rather than replacing older hardware that is no longer capable of running new Windows-based applications, you can use that older hardware much like a thin client to access the desktop and applications on the server rather than on the local computer.

Using the Remote Desktop Web Connection

The Remote Desktop Web Connection is an ActiveX control that provides virtually the same functionality as the executable version of Remote Desktop Connection, but it delivers this functionality over the Web even if the executable version is not installed on the client computer. When hosted in a Web page, the ActiveX Client Control allows a user to log on to a terminal server through a TCP/IP Internet or intranet connection and view a Windows desktop inside Internet Explorer.

The Remote Desktop Web Connection provides an easy way to offer Terminal Server through a URL. Consider using the Remote Desktop Web Connection in the following situations:

  • Roaming users. Users who are away from their computers can use Remote Desktop Web Connection to gain secure access to their primary workstations from any computer running Windows and Internet Explorer, provided they can reach the target computers.

  • Delivery of extranet applications. You can use Remote Desktop Web Connection to allow business partners or customers access to internal applications over the Internet. Users who gain access in this manner do not need to reconfigure their computers, and they do not gain access to your internal network.

  • Deployment transition. You can deploy the Remote Desktop Web Connection quickly and use it while you are deploying your full Remote Desktop Connection infrastructure.

Interactions with Other Technologies

Terminal Services depends on, or interacts with, the following technologies:

  • RDP Protocol - On the server, RDP uses its own video driver to render display output by constructing the rendering information into network packets using RDP protocol and sending them over the network to the client. On the client, RDP receives rendering data and interprets the packets into corresponding Microsoft Win32 graphics device interface API calls. For the input path, client mouse and keyboard events are redirected from the client to the server. On the server, RDP uses its own virtual keyboard and mouse driver to receive these keyboard and mouse events.

  • Terminal Server Interactions with RDP

    Terminal Server Interactions with RDP

The following resources contain additional information that is relevant to this section.