There are two types of Remote Desktop Services client access licenses (RDS CALs):
RDS Per Device CALs
RDS Per User CALs
The Remote Desktop licensing mode configured on a Remote Desktop Session Host (RD Session Host) server must match the type of RDS CALs available on the license server. For more information, see Specify the Remote Desktop Licensing Mode on an RD Session Host Server.
When Per Device licensing mode is used, and a client computer or device connects to an RD Session Host server for the first time, the client computer or device is issued a temporary license by default. When a client computer or device connects to an RD Session Host server for the second time, if the license server is activated and enough RDS Per Device CALs are available, the license server issues the client computer or device a permanent, RDS Per Device CAL.
An RDS Per User CAL gives one user the right to access an RD Session Host server from an unlimited number of client computers or devices. RDS Per User CALs are not enforced by RD Licensing. As a result, client connections can occur regardless of the number of RDS Per User CALs installed on the license server. This does not absolve administrators from Microsoft Software License Terms requirements to have a valid RDS Per User CAL for each user. Failure to have an RDS Per User CAL for each user, if Per User licensing mode is being used, is a violation of the license terms.
To ensure that you are in compliance with the license terms, make sure that you track the number of RDS Per User CALs being used in your organization and that you have a sufficient number of RDS Per User CALs installed on the license server to provide an RDS Per User CAL for each user that needs to connect to the RD Session Host server.
You can use the Remote Desktop Licensing Manager (RD Licensing Manager) tool to track and generate reports on the issuance of RDS Per User CALs. For more information, see Track the Issuance of Remote Desktop Services Per User Client Access Licenses.
In Windows Server 2008 R2, Remote Desktop Services provides the ability to deploy a virtual desktop infrastructure (VDI). Each device connecting to a Remote Desktop Services VDI deployment needs a Per Device VDI CAL. For more information about Per Device VDI CALs, see
For information about purchasing RDS CALs, see Purchase Client Access Licenses (
For more information about RD Licensing, see the Remote Desktop Services page on the Windows Server 2008 R2 TechCenter (