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: 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:
To correct this problem, change the Licensing Mode in Terminal Services Configuration to Per User. To do this, follow these steps:
- Click Start, point to Administrative Tools, and then click Terminal Services Configuration.
- Click Server Settings, and then double-click Licensing Mode.
- Change the Licensing Mode to Per User, and then click OK.
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: