Running Linux GUI Apps Remotely on Windows with SSH and X Server

When working on remote development via SSH, you sometimes need a graphical user interface (GUI). For example, I use ROS with VS Code on a Windows machine via SSH to access a Linux host. This guide explains how to set up and use an X server on Windows to run graphical Linux applications remotely via SSH.

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1. Install X Server for Windows

Download and install VcXsrv, a popular X Server for Windows, from the following link:

[VcXsrv Windows X Server download

SourceForge.net](https://sourceforge.net/projects/vcxsrv/)

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2. Start and Configure VcXsrv

Ensure that VcXsrv is running on your Windows machine and listening for incoming connections. Follow these steps to start and configure it:

1. Open VcXsrv (search for VcXsrv in your Start Menu).
2. Start a new X server session with the following options:
   • Display number: 0
   • Start no client: Leave this as it is.
   • Check the box for Disable access control (this allows all machines to connect to the X server without requiring special permissions).

Note: Disabling access control can pose security risks. Use this option only in trusted environments.

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3. Connect to the Linux Host via SSH

Use the ssh command with the -X flag to enable X11 forwarding:

ssh -X <username>@<host_ip_address>

Replace <username> with your Linux username and <host_ip_address> with the IP address of the Linux machine.

Tip: If your Linux host’s IP address changes frequently, consider setting a static IP address or using a hostname with DNS.

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4. Set the DISPLAY Environment Variable on Linux

On the Linux host, set the DISPLAY environment variable to point to your Windows machine’s IP address. Run the following command:

export DISPLAY=<local_ip_address>:0.0

Replace <local_ip_address> with the IP address of your Windows machine.

Tip: If your Windows machine’s IP address changes frequently, consider assigning it a static IP address.

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5. Allow Connections with xhost

Run the following command on the Linux host to allow connections to the X server:

xhost +

Note: Allowing all connections with xhost + is not secure. For better security, use xhost +<specific_ip> to allow only your Windows machine.

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6. Test Running an X Application

To verify that the setup is working, try running a simple X application like xclock:

xclock

If everything is configured correctly, the xclock application should appear on your Windows desktop.

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7. Running GUI Applications in Docker Containers

To run GUI applications inside a Docker container and display them on your Windows machine, use the following command when creating the container:

docker run -it --rm \
  --env DISPLAY=$DISPLAY \
  --env QT_X11_NO_MITSHM=1 \
  --volume /tmp/.X11-unix:/tmp/.X11-unix:rw \
  your_image \
  bash

• --env DISPLAY=$DISPLAY: Passes the DISPLAY environment variable to the container.
• --env QT_X11_NO_MITSHM=1: Fixes potential issues with shared memory in Qt applications.
• --volume /tmp/.X11-unix:/tmp/.X11-unix:rw: Mounts the X11 socket for communication between the container and the host.
• your_image: Replace this with the name of your Docker image.

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By following these steps, you can run graphical Linux applications on your Windows machine using an X Server and SSH.