Fully utilizing the services of a Windows Server environment requires the proper licenses.
Most people are aware of the need to license the server software itself.
If you are running a Windows Server environment, then you better know about Client Access Licenses.
This guide discusses what CALs are, who needs them, and what types of CALs are available.
What Are Client Access Licenses?
What Is the Difference Between a Server License and a Client Access License?
Server licenses are like operating system licenses on any standard PC or laptop.
The license grants the right to spin up the server software on a single server.
Although you may choose to purchase software to do this, there are no further licensing costs to consider.
The picture is different with a Windows Server License.
Do All Windows Server Services Require a CAL?
Not all Windows Server services require a CAL.
However, for server services including the ones listed below, CALs are normally required.
This is the point in the story where things start to become a little more complicated!
Because not only do each of these services require its own CAL.
But also, as we will discuss next, not all versions of Windows Server will require CALs.
Do All Versions of Windows Server Require CALs?
To muddy the water further: not all versions of Windows Server will require you to purchase CALs.
The most notable example of this is the Windows Server Essential edition.
This version allows up to 25 users and 50 devices to access server services without CALs.
They are one of the main determining factors to consider when you are planning the deployment of your server.
User and unit CALs: What Is the Difference?
As the names suggest, Microsoft issue CALs on a User or equipment basis.
A user CAL allows a single user access to the server.
Importantly, this can be from any capable gear.
A machine CAL is allocated to a single machine.
Any user that uses the licensed equipment has access to the server’s services.
This distinction needs to be considered carefully when you are choosing the right licensing model for your server deployment.
The diagram below is a simplified visual of the factors to consider.
Of course, the reality is rarely as simple as this.
But considering these factors allows you to set a baseline that is the foundation of your CAL licensing strategy.
TheMicrosoft Client Access Licence pagehas plenty more information about choosing the correct CAL.
