Guide to Windows Server licenses and CALs: how to choose without making mistakes
Discover how the Microsoft server licensing system works, what CALs are, and how to calculate the requirements for your company.
The server license alone is not enough
When installing Windows Server in a company, the first step consists of purchasing the license for the actual operating system. Many users think that this purchase is sufficient to allow all employees to start working. In reality, the server license only covers the installation of the software on the physical or virtual machine. To allow computers and people to connect to that server and use its services, Microsoft regulations require the purchase of additional access licenses.
Without these access licenses, the use of the server by computers on the company network does not comply with the terms of use. This mechanism applies to most network features, such as file sharing, printer management, or access to company databases. Therefore, the server software and the access permissions must be considered as two separate and complementary elements.
What are CALs and how do they work
The acronym CAL stands for Client Access License. It is not software to be installed on computers, but a legal right of use that is purchased to be compliant. Every time a user or a device interacts with Windows Server, it must be covered by a CAL. There are two main types of these licenses, and the choice between one and the other depends entirely on the organization of work in the company.
User CALs are linked to the individual person. Once the license is assigned to an employee, they can access the server from any device, such as their office computer, home computer, or company smartphone. Device CALs, on the other hand, are linked to the individual machine. Once the license is assigned to a computer or terminal, anyone using that device can access the server, but only from that specific workstation.
How to choose the type and calculate the number
The choice between the two types of CALs must be based on the calculation of economic convenience. If every employee in the company has their own desktop computer, a laptop, and a company phone, it is more convenient to purchase User CALs. In this way, you pay for only one license per person, instead of three licenses for the different devices used by the same worker.
Conversely, if the company organizes work in shifts, the situation changes. If three employees take turns during the day to use the same computer at the reception desk or in a production department, it is more convenient to purchase a single Device CAL for that computer. In this way, a single license covers the access of three different people. To calculate the total requirement, simply count the lower number between the total users and the total devices that need to interact with the server.
Difference between Standard and Datacenter
The choice of the Windows Server version affects the management of virtualization. The Standard edition is designed for companies that mainly use physical servers or that need to create very few virtual machines. Indeed, this license includes the right to run a very limited number of virtual environments on the same physical hardware.
The Datacenter edition, on the other hand, is designed for structures that make intensive use of virtualization. This version allows the creation of an unlimited number of virtual machines on the same physical server. From the perspective of CALs, the rules do not change. Whether you choose the Standard version or the Datacenter version, it is always necessary to purchase CALs for the users or devices that connect to the server's services.