Desktop Sharing via x11vnc+SSH

Introduction¶

x11vnc is a powerful VNC program. What makes x11vnc different from other VNC programs is an administrator can grab a user's existing X session rather than be forced to create a new one. This makes X11VNC ideal for providing remote support to Linux desktops.

This guide teaches you how to set up an X11vnc server and how to connect to it remotely.

Note

One of the main benefits of using x11vnc over SSH is that it eliminates the need to open any additional ports on your machine, thereby minimizing the attack surface.

Assumptions¶

For this guide, the assumption is that you have the following:

Rocky Linux Workstation
sudo privileges

Setting up the VNC server¶

To capture your X session, you must install the x11vnc server on your Rocky workstation.

Disable Wayland¶

First, you need to disable Wayland. Open the custom.conf file using your text editor of choice:

sudo vim /etc/gdm/custom.conf

Uncomment WaylandEnable=false:

# GDM configuration storage

[daemon]
WaylandEnable=false

[security]

[xdmcp]

[chooser]

[debug]
# Uncomment the line below to turn on debugging
#Enable=true

Restart gdm service:

sudo systemctl restart gdm

Install and configure x11vnc¶

Enable the EPEL repository:

sudo dnf install epel-release

Create a password for x11vnc:

x11vnc -storepasswd ~/.x11vnc.pwd

Create a new file with your text editor of choice. You will use this to create a service to run x11vnc:

sudo vim /etc/systemd/system/x11vnc.service

Copy and paste the following text into the file, then write and quit:

Note

Replace the rfbauth path with the path to the password file you created earlier. Also, replace the User and Group values with the user to whom you intend to provide remote support.

[Unit]
Description=Start x11vnc at startup
After=display-manager.service

[Service]
Type=simple
Environment=DISPLAY=:1
Environment=XAUTHORITY=/run/user/1000/gdm/Xauthority
ExecStart=/usr/bin/x11vnc -auth /var/lib/gdm/.Xauthority -forever -loop -noxdamage -repeat -rfbauth /home/server/.x11vnc.pwd -rfbport 5900 -shared
User=server
Group=server

[Install]
WantedBy=multi-user.target

Enable and start the x11vnc service:

sudo systemctl enable --now x11vnc.service

Connecting to the VNC server from your Rocky workstation¶

Install the EPEL repository¶

sudo dnf install epel-release

Install a VNC client¶

Install TigerVNC. The server is not used, but you will use the client:

sudo dnf install tigervnc

Create the SSH Tunnel¶

The ssh command in a terminal window

Create an SSH tunnel to connect to the VNC server securely:

ssh -L 5900:localhost:5900 REMOTEIP

Launch the VNC Viewer¶

Open your VNC viewer with the following command:

vncviewer

TigerVNC viewer

Connect to the VNC server by entering 127.0.0.1 or localhost into TigerVNC and connect.

TigerVNC viewer password prompt

Enter the x11vnc password you created earlier.

TigerVNC viewer connected to an X session

Congratulations! You can now remotely control the desktop!

Connecting to a machine across the internet¶

So far, this article has shown you how to set up an x11vnc server and connect to it using VNC forwarded through an SSH tunnel. It is important to note that this method will only work for computers on the same local area network (LAN). Assuming you want to connect to a computer on a different LAN. A way to accomplish this is to set up a VPN. Below are a few guides on how to set up a VPN:

Conclusion¶

Congratulations! You have successfully set up an x11vnc server and connected to it using a TigerVNC client. This solution is ideal for remote support, as it shares the same X session as the user, ensuring a seamless support experience.

Author: Joseph Brinkman

Contributors: Steven Spencer, Ganna Zhyrnova