Ensure Your Customers’ Windows Server 2016 Client Access License (CAL) Needs are Filled!

In our recent blog, “Microsoft Windows Server 2016's core-based licensing explained” we discussed the new core-based licensing structure introduced with Microsoft Windows Server 2016. It is important to remember that this licensing model includes both Cores + Client Access Licenses (CALs) so you must ensure that your customers have the right number of Client Access Licenses (CALs) for their IT needs. 

If your customers are running Microsoft Windows Server on their HPE ProLiant Servers (a great combination in our humble opinion), they may need Client Access Licenses (CALs) to legally use the OS. To clarify, A CAL is not a software product. Rather, it is a license that gives a user or device the rights to access the services of the server. Licensing software with CALs can be complicated due to the technical nature of server products and networks but, we’re here to help make it as simple as possible.

BONUS: Learn more about CALs from our new Coffee Coaching session, Understanding Windows Server Client Access Licenses (CALs)


There are multiple CAL types: User CALs, Device CALs, and Remote Desktop Service (RDS) CALs.Types of CALs.jpg

User CALs: With the User CAL, a CAL is purchased for every user to accesses the server to use services such as file storage or printing, regardless of the number of devices they use for that access. User CALs deliver increased value and flexibility. With device proliferation and the move to BYOD (bring your own device), there is a growing trend of employees using more and more devices. Because of this,it is often times easier to track the number of users accessing the server, than the number of devices accessing the server.

Device CALs: With a Device CAL, a CAL is purchased for every device that accesses the server regardless of the number of users who use that device to access the server. Device CALs may make more economic and administrative sense if the company has workers who share devices, for example, on different work shifts.

RDS CALs: A Remote Desktop Service (RDS) CAL is also required for users that need to access programs or the full desktop remotely. Both a Windows Server CAL (User CAL or Device CAL) and a RDS CAL are required for remote desktop access.  

CALs can be purchased directly from HPE or from an HPE authorized reseller at any time and are available individually, or in packs of 5, 10, and 50.


Now that you understand what CALs are, the different types of CALs, and which type may be best for different business scenarios, and how to purchase CALs, we wanted to cover a few frequently asked questions we get regarding CALs for Windows Server 2016.


Windows Server 2016 CAL FAQs:

Q: Are CALs still required for Windows Server 2016?
A: Windows Server Standard and Datacenter Editions will continue to require Windows Server CALs for every user or device accessing a server (Essentials Edition does not require CALs). Some additional or advanced functionality will continue to require the purchase of a RDS CAL. RDS CALs are needed in addition to the Windows Server CAL to access functionality, such as Remote Desktop Services.

Q: Is it possible to buy additional CALs after I purchase the OS license? 
A: Yes, customers can buy additional CALs from HPE or HPE authorized resellers at any time and do not require a new HPE server purchase. HPE currently offers one, five, ten, and fifty CAL packs (user or device) and five CAL packs for RDS CALs (user or device).

Q: Can I use my Windows Server 2012 CALs to access Windows Server 2016?
A: No. CALs must be the same version as—or higher than—the server software they are accessing. In other words, users or devices accessing a server running Windows Server 2016 must have Windows Server 2016 CALs.

Q: Can I use my Windows Server 2016 CALs to access Windows Server 2012 R2?
A: Yes. A Windows Server CAL permits access to all earlier versions of Windows Server.


Want to learn more about HPE OEM Microsoft Windows Server 2016? Check out the Windows Server 2016 Product Page, DataSheet, and Licensing FAQ.

Have questions about CALs that we didn't answer? Leave us a comment here or drop us a note on any of our social media channels:



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Willa manages the HPE | Microsoft Coffee Coaching program. Follow along to learn more about the latest HPE OEM Microsoft product releases and how the HPE Microsoft partnership can benefit partners and customers.


Hello, I have Windows server 2016 install on my HP Proliant Dl380 Gen9. 

I also purchased a user CAL while purchasing this OS.

please how do I go about intsalling and activating this user CAL. 

Thank you!

Hi Uchnovy2017- to ensure we give you the correct answer can you please clarify if you purchased a regular User CAL or an RDS (Remote Desktop Services) User CAL? If it'd be possible to provide the part number that would be even better!


Shagul Hameed Dasthagir

Dear All,

We have recently purchased the User CAL's for one of our client. Kindly let me know how to configure this . Because I can find only Tracking Id. inside the pack. The pack name is (Windows Server 2016 CAL 5 USER) and the part number is R18-05244.




Hi Shagul Hameed Dasthagir,

Great question. Windows Server operating system (OS) user CALs do not get entered into the OS, meaning there is no configuration needed. There is no key on the license itself, only a tracking ID. If you have further questions on this please feel free to send us an email at


Recently purchased a HPE ProLiant DL380 Gen9 running Windows Server 2016 with the following...

30 x Microsoft Windows ServerCAL 2016 Sngl OLP 1License NoLevel UsrCAL

30 x Microsoft WinRmtDsktpSvcsCAL 2016 Sngl OLP 1License NoLevel UsrCAL

I have delivered 30 packets of Client Access Licence documents with a Tracking ID sticker on them but no way of inputting these in to the server licensing manager. How do you go about inputting these as the server is complaining the Remote Desktop Services are in a 'trial mode'  with only a few days to go!

Why do Microsoft make this so awkward?

Hi RocketTim, 
You can find more information on installing RDS Client Access Licenses on the Remote Desktop license server here: 

John McSorley

I have the same problem. I have set up HPE ProLiant DL360 Gen9 running Windows Server 2016. I have went into Server Licencing Manager to install the licence. Server Licencing Manager requires 5 sets of 5 alphanumeric digits. The Client Access Licence bought from HP only contains a tracking number. Can somone explain how to install the Client Access Licence. The link to the video in the previous post only gives basic information, it does not address this problem. Any help would be greatly appreciated. Thanks.

Hey John,

The first thing that must be determined is whether you have Windows Server OS CALs or Windows Server RDS CALs.

A Windows Server OS CAL is required when a user or device is directly or indirectly accessing Windows Server. A Windows Server Remote Desktop Service (RDS) CAL is also required for users that need to access programs or the full desktop remotely using Remote Desktop Services (RDSs). Both a Windows Server CAL (user or device) and a RDS CAL (user or device) are required for remote desktop access.  In addition, RDS CALs contain a product key for activation. As an exception to these rules, up to two users or devices may access the server software, only for server administration purposes, without requiring either a RDS CAL or a Windows Server CAL.

Windows Server OS CALs do not need to be activated and they do not get entered into the OS. They are for tracking purposes/proof of licensing. 

If you are trying to activate Windows Server RDS CALs you can get instructions here: Install RDS client access licenses on Remote Desktop license server

If you have more questions please feel free to email us at so we can gather information about your specific server requirements. 



 every user to accesses the server to use services such as file storage or printing, regardless of the number of devices they use for that access. this is really a vital information for us.


I have a server (not more than 2 CPU/12 cores) with Windows Server 2016 Standard (that's how it came).  There will be only one other user accessing the services of the server.  I just want to confirm if I will simply need 2 User CALs.  For filesharing, MS 365, printer services (possibly) are all it will be used for.  I won't be using it commercially either.  It's on a simple home server.