VirtualBox has a built-in server with a Remote Desktop Protocol (RDP) service that allows users to connect to virtual machines remotely from another computer. This method is called ‘Remote Display’. This guide explains how to set it up, connect and use multiple remote displays in Oracle VirtualBox.
The best part of the remote display is it doesn’t require any network connection between VirtualBox virtual machine and other network computers from where you want to connect. The only network connectivity required is between the VirtualBox host computer (Where VirtualBox is installed) and the physical computer you are trying to connect.
The remote display option in VirtualBox helps to reduce the workload of the host computer. For example, when you have several virtual machines on a single host computer, you can start those virtual machines in headless mode (VM runs in the background without any console view) and connect remotely from other computers. So, it reduces the graphics and video output requirements/resources on the host computer.
How to Enable Remote Display in VirtualBox Virtual Machine
1) Go to the Display option in the settings of the particular virtual machine.
2) Click on the Remote Display tab.
By default, remote display options are disabled in VirtualBox. Click Enable Server option as shown above.
The default port is 3389, Authentication method can be changed as per your security requirements.
With the above steps, we successfully activated the remote display for the particular virtual machine. We can take RDP and control this machine from any other network computer.
How Remote Display Works in VirtualBox
The remote display in VirtualBox is not at all connected with the guest Operating System of the virtual machine. When the remote display server is enabled for a particular virtual machine, the VirtualBox console broadcasts the virtual machine’s output window through the specified TCP port via the host IP address. Therefore any remote desktop (RDP) request that comes to the host computer via this port number will get the virtual machine’s display based on the authentication method.
How to Connect Remote Display in VirtualBox
Use any Remote Display Protocol (RDP) viewers; Windows Remote Desktop Connection can be used to connect a remote display.
1) Open remote desktop connection on any other computer which can communicate to VirtualBox host (Physical) computer.
2) Type the IP address of the host machine with the port number.
IP Address: Port number (the same port number we specified during remote display settings in the virtual machine)
3) As shown below, I got the remote desktop connection and was able to view/work on the virtual machine no matter what operating system it is. I could connect to Mac OS virtual machine from Windows 10 host.
How to Connect Multiple Remote Displays
Okay, now the question is how to connect multiple virtual machines using a remote display? We can connect all virtual machines while using the VirtualBox RDP server with different port numbers.
The remote display server port for each virtual machine should be different to enable multiple remote connections. For example, when my macOS virtual machine has server port 3389, another machine can have 3388 or 3387 or any available ports on the host computer. The remote display server port numbers can be changed as mentioned earlier.
Each virtual machine can be connected and controlled by a remote desktop viewer by typing VirtualBox server host IP with different port numbers.
Make sure that the firewall on the host computer is set to allow remote desktop protocol (RDP) connections and these port numbers.
Remote Display in VirtualBox is a nice feature to reduce resource usage on the host computer. Also, the remote display feature enables multiple users from multiple computers to access virtual machines that are hosted on a single VirtualBox server host computer. This will be an idea for the testing environment.
Feel free to share your experience with the remote display feature on Oracle VirtualBox.