In order to install Parallels RAS on Windows servers, there are some required prerequisite to be installed from the Server Roles and Features.
RAS Connection Broker can be installed on any supported version of Windows. The Connection Broker does not require any specific Windows roles or features.
The Secure Gateway can be installed on any supported version of Windows. The Secure Gateway does not require any specific Windows roles or features.
RAS RD Session Host Agent requires the Terminal Server Role on Windows Server 2008.
RAS RD Session Host Agent is supported on the following operating systems:
Windows Server 2008 up to Windows Server 2019
Windows Server 2016 and newer must be installed using the "Desktop Experience" installation option.
Windows Server 2012 R2 — Server Core installation option is not supported.
In Parallels RAS v15 and newer, the Remote Desktop Session Host role can be automatically installed using the "Add Terminal Server" capability in the RAS Console.
Parallels RAS does not replace the need for Microsoft Client Access Licenses (CALs). A Windows Remote Desktop/Terminal Server License server is required.
Except for very small, single-server environments, the License Server should not be installed on the production Terminal Servers or Remote Desktop Session Hosts.
More information on TS/RDS CALs can be found at https://technet.microsoft.com/en-us/library/cc753650(v=ws.11).aspx.
Ensure that Desktop Experience is installed on all Terminal Servers
When a user connects a Parallels RAS server, the desktop that exists on the RD Session Host server is reproduced in the remote session by default. To make the remote session look and feel more like the user's local Windows desktop, install the Desktop Experience feature on an RD Session Host server that is running Windows Server 2008 R2, Windows 2012, Windows 2012 R2. Note that Windows 2016 has the Desktop Experience feature enabled by default on RDS host. This also makes the graphics look better using the Windows Aero theme.
Desktop Experience is a feature that you can install from Server Manager.
Once Desktop Experience is enabled, you will notice that applications display richer graphics and a remote desktop looks more like the client's local desktop with themes and other Windows client components.
