Vnc to a headless server with X11vnc
A few people have found my guide for setting up VNC access on a headless box useful on GitHub, so I thought I’ll aim low and publish that same guide as one of my first posts here. It should be noted that I think Wayland makes the same setup possible with less hassle, but GNOME being the only truly usable DE on Wayland at the time of writing, it is a bit heavy for remote access. At least in my experience even on a gigabit LAN connection, the animations need to be turned off to escape the feeling of running out of bandwith.
Instructions are adapted from these instructions on Steam x11vnc man page Arch wiki page for x11vnc and various tutorials/blog posts online
You will get a single always-on local desktop session to which you can login via VNC. No multiple sessions or users!
Prerequisites:
- A linux system with a working graphical environment on X11
- install the system with a monitor, keyboard and mouse plugged in. You’ll need a way to generate the edid.txt file and
/etc/X11/xorg.conf
. I had an NVIDIA card so I usednvidia-settings
to do that. On AMD/Intel graphics you should be able to usesudo Xorg -configure
( https://www.cyberciti.biz/tips/create-a-xorgconf-file.html), but I haven’t tried this. You can also use the edid.txt provided in the Steam instructions link above, there are options for 1920x1080 and a 1440x900 monitors. Copy and paste the EDID informations to e.g./etc/X11/edid.txt
.
- install the system with a monitor, keyboard and mouse plugged in. You’ll need a way to generate the edid.txt file and
x11vnc
installed- You can unplug the monitor and peripherals after you have generated the
xorg.conf
andedid.txt
- an SSH server running is a good idea so you have some other way of accessing the headless box
- I’ve tried this with Xfce, MATE, LXQt and GNOME, so I assume most DEs will work, but the experience is better on a lighter DE with few or no animations
- I’ve tested on Fedora, CentOS, Ubuntu and Ubuntu MATE, and the above instructions (Steam) are for Arch Linux, so most distros will probably work. There might be slight differences you’ll have to figure out yourself
Acquiring xorg.conf
and edid.txt
on NVIDIA
Install the NVIDIA proprietary drivers, log in to an Xorg session of your chosen desktop environment. Open a terminal and run
sudo nvidia-settings
(sudo is required so you can generate/etc/X11/xorg.conf
Generate
/etc/X11/xorg.conf
:- from “X Server Display Configuration, click “Save to X configuration file” and set the path
/etc/X11/xorg.conf
- from “X Server Display Configuration, click “Save to X configuration file” and set the path
Generate
/etc/X11/edid.txt
: (or use the provided one, you can also save this anywhere you like)- From the list of ports, choose the one your monitor is connected to (for me it was DVI-I-1) and click “Acquire EDID”, then select EDID File Format as ASCII. Save the file somewhere, I used
/etc/X11/edid.txt
- From the list of ports, choose the one your monitor is connected to (for me it was DVI-I-1) and click “Acquire EDID”, then select EDID File Format as ASCII. Save the file somewhere, I used
Edit
/etc/X11/xorg.conf
and in the<Device>
section add the lines:ReplaceOption "ConnectedMonitor" "<display>" Option "CustomEDID" "<display>:<path>/edid.txt"
<display>
and<path>
with yours, for me it wasOption "ConnectedMonitor" "DVI-I-1"
andOption "CustomEDID" "DVI-I-1:/etc/X11/edid.txt"
Save the file
Edit (create)
/etc/X11/Xwrapper.config
:- add the line
allowed_users=anybody
- this will allow the X session to be started anywhere, It seems this is necessary to start X without an attached display. You can try without it too.
- add the line
You can disconnect the monitor at this stage if you want, but for troubleshooting it’s better to keep it connected
Make GDM use Xorg instead of Wayland:
- edit
/etc/gdm/custom.conf
and uncomment the lineWaylandEnable = false
Set up automatic login:
For GDM: (Ubuntu) Arch wiki
- Under the
[Daemon]
section in/etc/gdm/custom.conf
, addAutomaticLogin=username AutomaticLoginEnable=True
- replace
username
with your username - you can also do this from the GUI if you still have the monitor attached
- edit
/var/lib/AccountsService/users/<username>
and make sure theXSession=<your preferred DE>
is correct. The possible sessions are in/usr/share/xsessions
, use one of those without the.desktop
extension. This should be correct if you have only one DE installed.
- Under the
For SDDM: Arch wiki
- create the file
/etc/sddm/sddm.conf.d/autologin.conf
with the following content:[Autologin] User=<username> Session=<session>.desktop
- replace
<username>
and<session>
with your values
- create the file
For other DMs you can find instructions online
Test that everything is working so far
- Reboot and see that you get logged in correctly to an Xorg session with the display still connected. If you already disconnected the monitor, SSH in and check that your user is logged in on tty :0
Set up x11vnc
install
x11vnc
if you haven’t alreadyGenerate a password for the VNC session:
- run
x11vnc -storepasswd
as your regular user - Please note that VNC is by default unencrypted! If you use this over the internet, I suggest using a VPN connection or tunneling over SSH
- You can also set up the VNC to be encrypted, but I used a VPN (Wireguard)
- run
Make sure at least port 5900 is open in your firewall. The server might be using other ports too, and the clients can autodetect the port, so it’s a good idea to open ports 5900-5903.
Test:
- run
x11vnc -usepw
- connect from another machine using VNC client software of your choosing
- there are other options for the VNC server, such as
-noxdamage
, but I haven’t got so far as to try any of them out. You could probably improve performance a lot by experimenting with different options. The output of the above command gives good hints. Note that when you disconnect the VNC client, with the above command the VNC server terminates, and to connect again, it must be started again. We’ll set up automatic starting next
- run
Once you have tested that the server and connecting to it works, create an autostart desktop file
~/.config/autostart/x11vnc.desktop
:[Desktop Entry] Name=x11vnc Comment=VNC server Exec=/usr/bin/x11vnc -usepw -loop -forever Type=Application NoDisplay=true X-GNOME-Autostart-enabled=true
- note the
-forever
and-loop
options,-forever
makes the server not quit when the client connection is closed, and-loop
makes the server try restarting even if the X server is terminated/restarted. Add any other useful options you want.
- note the
Reboot
Test that the connection is working
Shut down, disconnect the monitor and peripherals and power on, then test that everything is working
Notes:
- This gives you a Windows remote support like experience, where you log in to the “physical” session via VNC. If you tested the VNC connection with the monitor attached, you can see the mouse moving on the local screen and everything is “real time”
- No multiple logins at a time this way
- It’s probably a good idea to experiment with the different flags x11vnc offers. For my use case these very basic ones have been ok so far.
- There are better ways to handle the automatic starting, like systemd units, but this way the process runs as non-root and works quite consistently.
- If you want to use the display managers login screen, see the Arch wiki, there are lots of tips there.
- DON’T log out. Disconnect the VNC client instead. If you log out, the VNC server is stopped and you’ll have to reboot to get back to a graphical session. Maybe restarting your display manager via SSH might be enough, but I haven’t tested it
- Share if you find this useful! There might be mistakes, please let me know and I’ll fix them
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