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Windows Server CALs

Last updated on May 31st, 2019

What is a CAL?

CALs are commonly misinterpreted as a software product. However, this is not the case. A CAL, or Client Access License, is rather a license that grants a user or device the rights to access the services of the Server. A good rule of thumb is that you are connecting to a Server in any way (file sharing, printing, Active Directory, etc.) a CAL is required. Although you can still technically use the services, it goes against Microsoft’s end user licensing agreement (EULA), i.e, breaking the law! Read on to see what type of licensing you may need —

Do I need User CALs or Device CALs?

You’ll probably run into this dilemma more often than you think. A quick, easy way to look at it is as follow —

Per User: 1 User -> Multiple Devices
Per Device: 1 Device -> Multiple Users

User CALs are recommended if the employees need to have roaming access to the corporate network using multiple devices, or if you have more devices than users.

Device CALs are recommended for businesses that have workers who share computers (time-clock terminals for shift employees, POS systems). These are also required for network devices such as printers or scanners.

Remote Desktop CALs?

In addition to Local CALs, any user/device connecting to the server using Remote Desktop Services (RDS) requires what’s known as an RDS CAL. Formerly known as Terminal CALs, RDS CALs follow the same licensing convention as local Server CALs.

RDS User CALs – When licensing per user, licensing is not enforced and can be over-allocated. Each user is granted a license to connect to the RD Session Host distributed from a license pool. If no CALs are in the available pool, they are pulled from the over-used CAL pool. Having over-allocated licenses is a violation of Microsoft’s EULA.

  • Assigned to a user in Active Directory
  • Tracked but not enforced by the server
  • Cannot be tracked within a workgroup
  • Temp CALs unavailable
  • Can be over-allocated (in breach of EULA).

RDS Device CALs – When licensing per device, a temp license is issued for the first time the device is connected to the RD Session Host. The second time the device connects it will be issued a permanent RDS Device CAL as long as there are CALs available and the server is activated.

  • Physically assigned to each device
  • Tracked and enforced by the license server
  • Can be tracked regardless of Active Directory membership
  • Up to 20% can be revoked
  • Temp CALs available for 52-89 days
  • Cannot be over-allocated

CAL Versions

CALs issued to users or devices must match the version of Windows Server that they are connecting to.

RDS license servers can host licenses from all previous versions of RDS and the current version of RDS. You cannot use older CALs to access newer Windows Server versions. Alternatively, you can use newer CALs to access older Windows Server versions.

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