Being able to access a Remote Desktop host server, a user or device requires Client Access License (CAL). CALs are issued by a Remote Desktop Services (RDS) license server to the requesting RDS Session host server which in turn grants access to a client (user or device) to use the server’s resources via remote desktop.
In this article we will look at how to install and activate your RDS license server and subsequently install the required CALs.
Understanding the RDS CAL model
There are two (2) types of RDS CALs:
- Per Device CAL
- Per User CAL
These allow either a user or a device to access the resources hosted on your RDS host server. There are some key differences between the two. Click here for more details on CAL type differences.
The main thing, however, from a high level, to keep in mind when selecting the correct type of license model for your environment, is this; when using the Per User CAL model one user can be granted a RDS CAL, and that user can access your server from any number of devices. This model is perfect for environments where one user is assigned their own dedicated device (computer, laptop etc.)
However, for the Per Device CAL model, one device is assigned a CAL and that device can be used by any number of users. This model is perfect for environments where multiple users use one device (computer, laptop, etc. like shift workers)
To sum it up:
- Per User CAL – One user → many devices
- Per Device CAL – One device → many users
ICAL version compatibility
CALs and RDS Session Host Servers
When connecting to a RDS host server the CAL version being used must be compatible with that server. An earlier CAL version cannot be used to access a later version Windows server, however the reverse is possible. For example, a RDS 2012 CAL cannot be used to connect to a RDS session host running Windows Server 2016. It can only connect to its current server counterpart and older. But, a RDS 2016 CAL can be used to connect to a server running Windows Server 2012. They are backward compatible but not forward compatible.
To sum it up:
- RDS CAL version C connects to RDS host server version C and older (version B, A), but cannot connect to RDS host server version D or onwards
Click here for more details on CAL compatibility with RDS session host.
CALs and RDS License Servers
Similar to the RDS session host, RDS CALs must meet compatibility requirements for the RDS license server that they are installed on.
Any RDS license server can host licenses for its current and previous versions of RDS. For example, a 2012 RDS license server can host 2012 and 2008 RDS CALs. However, a RDS license server cannot host CALs that are younger than its current version. This makes RDS licence servers backward compatible but not forward compatible as it relates to the installation and use of CALs on that server.
To sum it up:
- RDS license server version C can host RDS CALs version C and/or older (version B and A)
- RDS license server version C cannot host RDS CAL version D and/or newer CALs (version D, E, etc.)
Click here for more details on CAL compatibility with RDS license server.
How to install the Server roles
Follow these instructions to install the RD Licensing role on a Windows server. These visual steps were derived from Windows Server 2016. However, click here for general instructions from Microsoft’s website.
Log into your desired server with your administrator account. Type “server manager” in the Windows search bar, then click Server Manager to open up the Server Manager console.
Click “Add roles and features” under Configure this local server in the Server Manager window.
Click Next at the “Before you begin” window.
Select Role-based or feature-based installation then click Next.
Select the option Select a server from the server pool, then highlight your desired server by clicking on it, then click Next.
Choose Remote Desktop Services then click Next.
Click Next at the Features window (we are leaving the defaults)
Click Next at the Remote Desktop Services window (we are leaving the defaults)
Select Remote Desktop Licensing option under Role Services.
Select Add Features at the pop-up window.
Select the Remote Desktop Session Host option (If the Remote Desktop Session Host role has not been installed).
Click Add Features at the pop-up window.
You’ll realize that both Remote Desktop Licensing and Remote Desktop Session Host are now selected. Click Next to move on.
Select Restart the destination server automatically if required checkbox then Yes at the restart prompt.
At this point the server will begin installing the roles and necessary features, then reboot automatically. When you have logged in after the reboot the below window will pop-up to show that the installation has succeeded.
The RDS license server role has now been successfully installed.
How to activate the RDS license server
Now that the RDS license server has been installed it’s now time to activate it. Let’s do that.
Open Server Manager and Select Tools → Remote Desktop Services → Then click Remote Desktop Licensing Manager.
The RD Licensing Manager window will now pop up.
Click the “plus” sign next to the All servers option, then right-click your server name and select Activate Server.
Click Next at the Welcome to the Activate Server Wizard window.
Leave the Connection method at Automatic connection (recommended) then click Next.
Fill out the relevant Company Information at the next two dialog boxes then click Next.
Uncheck the Start Install Licenses Wizard now checkbox. Then click Finish.
That’s it! Your RD Licence server has now been successfully activated.
How to install RDS CALs
We have now completed the foundational requisite tasks to be able to install and use CALs. Let’s proceed to get that done.
Open Server Manager and Select Tools → Remote Desktop Services → Remote Desktop Licensing Manager
Right-click on your server name, then select Install Licenses.
Click Next at the Welcome to the Install Licenses Wizard page.
Select the License program through which you purchased your license, then click Next. In this example, we will select the “Service Provider License Agreement” option.
Enter your Agreement number then click Next.
Select the Product version and the License type. Then select the Quantity and click Next.
Note: Product version is the CAL version, CAL type is either Per Device or Per User CAL and Quantity is the number of licenses being installed.
We have now successfully installed our RDS CALs on the RDS License server.
How to troubleshoot the installation
There are other tasks that may need to be completed before your installed CALs can be used. If there are pending tasks you will see a warning sign beside your server name in the RD Licensing Manager. We can review the configuration and remedy those issues. Let’s do that.
Follow the below steps to troubleshoot the installation.
Right-click on your server name in the RD Licensing Manager window then select Review Configuration.
There are two conditions that must be met:
- The license server must be a member of the Terminal Server License Servers group in Active Directory Domain Services.
- The license server must be registered as a service connection point (SCP) in Active Directory Domain Services.
In our example condition 2 was met, however condition 1 was not. We will fix that in the next steps. Note that if condition 2 is not met. You will see a button to the right, similar to the first condition that will say . You would click that button to fulfil the condition.
Click Add to Group, then click OK.
You may be prompted to restart the Remote Desktop Licensing service after you have clicked Add to Group as outlined above, as seen below. Follow the next steps to get that done.
Find the Remote Desktop Licensing service by typing “services.msc” at the windows search bar then click the Services desktop app.
Search for the Remote Desktop Licensing service from the list. Select it, then right-click it and click Restart.
After the service has been restarted close the Services window and open Remote Licensing Manager once again if it was closed. Right-click your server name and Review Configuration again.
You’ll now see that the two conditions are now met.
In the RD Licensing Manager window you will now see a green tick beside your server name.
This is an indication that you have successfully installed your RDS CALs and they are ready to be used.
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