Terminal Server Licensing overview

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

Terminal Server Licensing overview

Terminal Server has its own method for licensing clients that log on to terminal servers, separate from the licensing method for Microsoft® Windows Server 2003 family operating system clients. When a client connects to a terminal server, the terminal server determines if a client access license (CAL) is needed. The terminal server then requests a CAL from the Terminal Server license server, and then the CAL is issued to the client by the terminal server. Although Terminal Server provides a licensing grace period during which no license server is required, after the grace period ends, clients must receive a valid CAL issued by a license server before they can log on to a terminal server.


  • If you use Remote Desktop for Administration, two concurrent connections can log on. You do not need a Terminal Server license server for these connections. For more information on Remote Desktop for Administration, see Remote Desktop for Administration overview.


To use Terminal Server, you must also have at least one license server. For small deployments, it is acceptable to install both the Terminal Server and Terminal Server Licensing service on the same physical computer; however, for larger deployments, it is recommended that Terminal Server Licensing be installed on a separate server.

Before installing Terminal Server Licensing, verify that the operating system of the license server will be compatible with the operating system of the terminal server. Note the following:

  • A Windows 2000 license server cannot issue CALs to terminal servers running Windows Server 2003 operating systems.

  • A license server running a Windows Server 2003 operating system can issue CALs to terminal servers running Windows Server 2000 or Windows Server 2003, or to terminal servers running Windows Server 2000 and terminal servers running Windows Server 2003 in a mixed environment.

After you install Terminal Server Licensing, you must activate the license server so that the license server can issue permanent CALs for Terminal Server clients. After the license server is activated and you purchase CALs, it provides a secure way to install, and issue permanent CALs to Terminal Server clients. If you do not activate a license server, it issues temporary CALs, which allow clients to connect to the terminal server for 90 days.

Terminal Server Licensing Components

Following are descriptions of the primary Terminal Server Licensing components:

Microsoft Clearinghouse

The Microsoft Clearinghouse is the facility that Microsoft maintains to activate license servers, issue CALs to license servers, recover CALs, and reactivate license servers. The Clearinghouse stores information about all activated license servers and CALs that have been issued. This information helps you track client usage of the terminal servers within your organization to ensure that you have purchased a sufficient number of CALs. The Clearinghouse is accessed directly when you choose the Internet (Automatic) activation method in the Terminal Server Licensing Activation Wizard. If you do not have Internet connectivity, you can also contact the Clearinghouse by phone. For more information, see Locate the Microsoft Clearinghouse telephone number for your country or region.

You cannot purchase CALs through the Microsoft Clearinghouse. For information about purchasing CALs, see Purchase client access licenses. After you purchase CALs, make sure to retain the License Purchase Agreement information. Having this information with you will facilitate communication with the Microsoft Clearinghouse, should you need assistance with recovering CALs or other Terminal Server Licensing tasks that are supported by the Clearinghouse.

License server

A license server stores all client licenses. A terminal server must be able to connect to an activated license server before clients can be issued permanent CALs.

Before installing the license server, determine which of the two license server roles you require—a Domain license server or an Enterprise license server. During Terminal Server Licensing setup, you select one of these roles. By default, a license server is installed as an Enterprise license server. For more information, see Terminal Server license server roles.


  • You must configure Terminal Server Licensing correctly in order for your terminal server to continue to accept connections from clients. To allow ample time for you to deploy a license server, Terminal Server provides a licensing grace period, during which no license server is required. During this grace period, a terminal server can accept connections from unlicensed clients without contacting a license server. The grace period begins the first time the terminal server accepts a client connection. It ends after you deploy a license server and that license server issues its first permanent CAL, or after 120 days, whichever comes first. For more information, see Terminal Server Licensing grace period.

To activate a license server, use the Terminal Server License Server Activation Wizard. When you activate a license server, Microsoft provides the server with a limited-use digital certificate that validates server ownership and identity. Microsoft uses the X.509 industry standard certificate for this purpose. The license server then uses this certificate to obtain and issue CALs to clients. For information about activating a license server, see Activating a Terminal Server license server.

Terminal server

A terminal server is a server on which the Terminal Server component of the Windows Server 2003 operating system is installed. A terminal server gives clients access to Windows-based applications that run entirely on the server, and supports multiple client sessions on the server. If a client does not have a license, the terminal server requests one from the license server. For instructions on installing Terminal Server, see Installing Terminal Server.


  • You can use any computer running Windows Server 2003 family operating systems to administer servers remotely with Remote Desktop for Administration (formerly Terminal Services in Remote Administration mode). You do not need to install Terminal Server. A license server and the Terminal Server Licensing administrative tool are not required for Remote Desktop for Administration. For more information about Remote Desktop for Administration, see Remote Desktop for Administration.

Client licenses

After the Terminal Server Licensing grace period ends, you must purchase and install the appropriate number of CALs for each device or user that needs connect to a terminal server. In addition, you must verify that the Terminal Server Licensing mode that you specify matches the type of CAL available on the license server. Terminal Server Licensing modes determine the type of CAL that a license server issues to a client. In Windows Server 2003, two types of CALs are available: Per User and Per Device. A Per Device CAL gives each client computer or device the right to access a terminal server that is running a Windows Server 2003 operating system. A Per User CAL gives one user the right to access a terminal server from an unlimited number of devices. In this case, only one CAL is needed instead of a CAL for each device.

When the Per Device licensing mode is used, and a client logs on to a terminal server for the first time, the terminal server issues the client a temporary license by default. When a client logs on to a terminal server for the second time, if the license server is activated and enough Per Device CALs are available, the terminal server issues the client a permanent, Per Device CAL. Per User CALs are not monitored by Terminal Server. This means that even though there is a Per User CAL in the license server database, the Per User CAL is not decremented when it is used. Additionally, if you use the Per User licensing mode, when a client logs on to a terminal server for the second time, the temporary license is not upgraded to a permanent CAL.

For instructions on configuring the Terminal Server Licensing mode, see Configure the Terminal Server Licensing mode. For information about the types of licenses supported by a license server that runs Windows Server 2003 family operating systems, see Required licenses.


For more information about Terminal Server and Terminal Server Licensing, see: