Client Access License
The Client Access License ( CAL ; German CAL ) is a special form of license management , primarily in Microsoft 's distributed products.
In order to be able to access a server , it is not only necessary to obtain licenses for the server and client themselves, but also to acquire client access licenses through which the server is licensed to accept client connections. There are two licensing options: either the licenses can be purchased per device (client) so that any user of this device can access server services, or the licenses are purchased per user, which means that a user can use server services from any device .