You must activate a license server before it can issue Remote Desktop Services client access licenses (RDS CALs) to Remote Desktop clients. Activation allows the license server to make subsequent secure transactions with Microsoft and receive RDS CALs. After you have activated your license server, it becomes a registrar for the RDS CALs. While waiting to complete the activation process, your license server can issue temporary CALs for clients that allow them to use Remote Desktop Services for up to 90 days. To complete the activation process, you need the product ID listed in the Remote Desktop Licensing Manager tool.