Parallels® Remote Application Server (RAS) Quick Installation Guide

Throughout this blog post, we will demonstrate the easiest way to install and configure Parallels® Remote Application Server (RAS) to deliver published applications and desktops to any users’ device. 

RAS Quick installation diagram

As you can see in the left side in the above diagram, the device is connected to the Internet via WAN, which then passes through the firewall and connects to Parallels RAS. 

On the other side, you can see in the Site 1 container that the devices and active directory are connected to the LAN inside the site. The LAN connection is also connected to Parallels RAS. 

Once the device is successfully connected to Parallels RAS, the published applications can be accessed from the device. The client connection flow consists of two stages: application enumeration and application launching. The points illustrated below describe each stage in detail. Please note that the steps described applying to all other types of published resources (not just applications), including remote desktops, documents, Web applications, and network folders. 

Application Enumeration 

Application enumeration is the process of getting the list of published resources that a particular user can access. During this stage, the following steps take place: 

  1. A user launches the Parallels Client on their device and opens a Parallels RAS connection (provided that it has been configured). 
  2. The Parallels Client connects to the Parallels RAS Secure Client Gateway or the HA-LB appliance if there is one installed. 
  3. If HA-LB is installed, the HA-LB appliance forwards the Parallels Client to the Secure Client Gateway according to load balancing rules. If HA-LB is not engaged with SSL offload (HA-LB is not installed or the pass-through mode is in place), an SSL session between the client and Parallels RAS Secure Client Gateway is established. 
  4. Parallels RAS Secure Client Gateway builds a connection tunnel with a Publishing Agent to initiate client authentication. 
  5. If the user authentication is successful, the Publishing Agent returns the application list to the Parallels Client via the Secure Client Gateway SSL tunnel. 
  6. The application list is displayed in the Parallels Client window on the user’s device, so the user can select an application to launch.  

Application Launching 

This stage comprises the following steps: 

  1. The user launches an application. 
  2. The Parallels Client sends the request via the Secure Client Gateway tunnel to the Publishing Agent. 
  3. The Publishing Agent selects the least-loaded RDSH server and then sends its IP address back to the Parallels Client via Secure Client Gateway. 
  4. Depending on the connection mode selected on the client-side (see Client Connection Modes below), the Parallels Client connects to the RDSH server directly or via Parallels RAS Secure Client Gateway and passes the user credentials to it. 
  5. The RDSH server verifies the received credentials and, if they are valid, starts an RDP session. 

Please note that the installation phases are divided into five phases: 

Phase 1 – Installing Parallels® Remote Application Server

Phase 2 – Setting up Parallels® Remote Application Server

Phase 3 – Adding and Configuring RDSH Servers

Phase 4 – Adding and Publishing Applications

Phase 5 – Invite Users

Once all five phases have been accomplished, you can start publishing and delivering applications to clients, using any device, through Parallels RAS. 


The servers required to be installed and configured for Parallels RAS are: 


The preceding lists the bare minimum amount of servers required for you to operate Parallels RAS and deliver applications and desktops to users. 

Server 1 will be used to install Parallels RAS since the server needs to be a Windows Server 2008/2016 edition. 

Server 1 and 2 will be used for remote desktop services. All the applications that you would like to deliver to your users need to be installed on these servers. There are two servers listed with the same role as a backup. If one of the servers fails, the users may still access the applications via the second server. Also, in the event of Server 1 failing, Server 2 will take over the roles of the Parallels Remote Application Server. The Parallels Remote Application Server also offers load balancing to balance the load between the two servers. Moreover, Parallels RAS components will also be pushed to Server 2 for high availability. 

Server 3 is the Parallels HA-LB (High Availability Load Balancing), which is a secure virtual appliance provided by Parallels for Hyper-V, VMware, and XenServer. The HA-LB virtual appliance is placed between client devices and Parallels RAS Secure Client Gateway. Multiple HA-LB appliances can run simultaneously, one acting as the master and the others as slaves. The more HA-LB appliances a Parallels RAS installation has, the lower the chance of end-users experiencing downtime. Master and slave appliances share a common or virtual IP address (also called VIP). Should the master HA-LB appliance fail, a slave is promoted to master and takes its place seamlessly without affecting end-user connections. 

By configuring the above-mentioned servers with Parallels RAS, you will be able to deliver applications to users’ device. This is the simplest and easiest way to set up your environment using Parallels RAS.