The function of Terminal Server CALs in Windows Server 2003


This article describes the function of client access licenses (CALs) in the Terminal Server Licensing client licensing management system in Microsoft Windows Server 2003.

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CALs in Windows Server 2003 are different from CALs in Microsoft Windows 2000. Windows 2000 only uses Device CALs. These CALs are tied to a device. Windows Server 2003 uses Device CALs, and it also uses a new client access license, User CALs. Device CALs in Windows Server 2003 function the same way that Device CALs in Windows 2000 do. User CALs, however, permit access to software by an individual user, instead of by a device.

User CALs allow customers more flexibility when they use Terminal Server in their environments. If a user logs on to more than one client computer, they use one User CAL. The User CAL is not stored in the registry on the client computer the way that a Device CAL is.

User CALs can only be installed on a Windows Server 2003 Terminal Server Licensing server. User CALs cannot be issued to Windows 2000 terminal servers or to clients that access Windows 2000 terminal servers. If the network contains Windows 2000 terminal servers, the Windows Server 2003 Licensing server also has to contain Device CALs, not just User CALs.

Customers do not need a Device CAL and a User CAL to access a terminal server. The terminal server is set in the Terminal Services Configuration tool under Server settings\Licensing as to which type of CAL it will accept. You can set this to Per Device or Per User. This setting can be changed without requiring a restart of the terminal server. One terminal server cannot accept User CALs and Device CALs at the same time.

If the Terminal Server is in Per Device mode and your Licensing server only contains User CALs, you are only issued temporary licenses. When these temporary licenses are close to expiration, you see the following message in a pop-up window:
Your terminal services temporary client license will expire in N days. Please contact your system administrator to get a permanent license.
This message also appears in the application event log as:To correct this problem, switch the terminal server to Per User mode.

Similarly, Terminal Server clients that run Microsoft Windows XP or Windows 2000 may receive the following error if the client cannot connect to the Terminal Server:
The remote session was disconnected because the local computer client access license could not be upgraded or renewed.
The following event is logged in the application event log on the Terminal Server computer:This problem may occur if the Licensing Mode in Terminal Services is set to Per Device, the Terminal Server Licensing server only has Per User CALS.

To correct this problem, change the Licensing Mode in Terminal Services Configuration to Per User. To do this, follow these steps:
  1. Click Start, point to Administrative Tools, and then click Terminal Services Configuration.
  2. Click Server Settings, and then double-click Licensing Mode.
  3. Change the Licensing Mode to Per User, and then click OK.
Currently, Windows Server 2003 does not manage User CALs. This means that even though there is a User CAL in the license server database, the User CAL will not be decremented when it is used. This does not remove administrators from End User License Agreement (EULA) requirements to have a valid terminal server (TS) CAL for each user. Failure to have a User CAL for each user, if Device CALs are not being used, is a violation of the EULA.

Note To use both User and Device TS CALs simultaneously on the same terminal server, the server must be configured for Per User TS CAL mode.

The following text is from the End User License Agreement (EULA) for Windows Server 2003:
Two different TS CALs are available to you: "Device" and "User." Each TS Device CAL permits one Device (used by any User) to conduct Windows Sessions on any of your Servers. Each TS User CAL permits one User (using any Device) to conduct Windows Sessions on any of your Servers. You may use a mix of TS Device CALs and TS User CALs simultaneously with the Server Software in your environment. You can have a Terminal Server request Per User licenses or Per Device (default) but not both simultaneously.


For more information about Windows Server 2003 Terminal Server Licensing, visit the following Microsoft Web sites: