> Well, if those devices use Windows server based services, then it makes more sense. But if they do not, Microsoft would have no way to know about their existe

> Well, if those devices use Windows server based services, then it makes more sense. But if they do not, Microsoft would have no way to know about their existence. Yes, that's exactly how it works. Windows Server Client Access Licenses (CALs) are sold either by user or by device. User licenses allow one person to use any Windows Server hosted services in the organization from any device. Device licenses allow any number of people to use any Windows Server hosted services from one specific device. If you have a bunch of users with their own personal computers and potentially other devices like a normal office the user CAL model usually makes the most sense, but for environments like classrooms or multi-shift businesses where you have significantly more devices than users the device CAL model can sometimes be beneficial. The catch is that almost any use of Windows services requires a CAL and that includes DHCP/DNS. If you host either of those services primarily from Windows the device count suddenly changes significantly.