What is a CAL?

Commonly misinterpreted as a software product.

The CAL(Client Access License) is rather a license that grants a user or device the ability to access the services of the server. If the workstations in your organization are part of a network, it is likely that you depend on network server software to perform specific functions such as file and print sharing. In order to access this server software legally, a CAL may be required. Follow this guide to keep informed on what type of licensing is right for you!

Here we will go over Server CALs for local network connections

User CALs

User CALs are the most commonly used license

and are used for servers that have users with an undetermined number of devices.

This model is recommended if your company's emloyees need to have roaming access to the corporate network using multiple devices or if you have more devices than users.

Device CALs

With Device CALs

you purchase a CAL for every device that accesses the server.

This model is more economic for organizations that have workers who share computers, for example, different work shifts.

Remote Desktop CAL's (RDS)

Remote Desktop CALs

A Remote Desktop CAL is required for any User or Device connecting to a Remote Desktop Session Host. When you connect to an RD Session Host, the Host server determines if an RDS CAL is needed. The Session Host server then sends a request for an RDS CAL from the RD license server. If a CAL is available from a license server, it is issued to the client, which then allows for a connection to the Host server and to the desktop or apps attempting to be used. The RDS CAL model is nearly identical to local client licensing.

Remote Desktop User CALs

Per User

CALs are assigned to a user in Active Directory.
CALs are tracked but not enforced by the server.
CALs cannot be tracked within a workgroup.
You cannot revoke any CALs.
Temporary CALs are not available.
CALs can be overallocated (in breach of the Remote Desktop licensing agreement).

When using the Per User model, licensing is not enforced and each user is granted a license to connect to an RD Session Host from any number of devices. The server issues licenses from the available CAL pool or the Over-Used CAL pool. It is your responsibility to ensure that all of the users have a valid license and 0 Over-Used CALs, otherwise it will be a violation of the RD licensing terms.

Remote Desktop Device CALs

Per Device

CALs are physically assigned to each device.
CALs are tracked and enforced by the license server.
CALs can be tracked regardless of Active Directory membership.
You can revoke up to 20% of CALs.
Temporary CALs are valid for 52-89 days.
CALs cannot be overallocated.

When using the Per Device model, a temporary license is issued for the first time the device is connected to the RD Session Host. The second time the device connects, as long as the server is activated and there are available CALs, the client is issued a permanent RDS Device CAL.

CAL Versions

CALs used by users or devices must correspond to the version of Windows Server that they are connecting to. Any RDS license server can host licenses from all previous versions of RDS and the current version of RDS. I.e., a Windows Server 2016 RDS license server can host licenses from all previous versions of RDS, while a Windows Server 2012 R2 RDS license server can only host licenses up to Windows Server 2012 R2.

*You cannot use older CALs to access newer Windows Server versions, but you can use newer CALs to access older Windows Server versions.