[root tip] [How To] TigerVNC - LAN connection to SDDM at display :0

Difficulty: ★★☆☆☆

This topic is a rewrite of the solution to ANY vnc server in kde with sddm - credit to @bedna for the original solution.


VNC is a protocol where you use your keyboard/mouse/screen to monitor or control a remote system.

:warning: :zap:
VNC is per definition insecure
Opening a VNC service onto insecure networks like the internet, public libraries, internet cafès etc. may lead to information leaking and/or attempts to take control of your system.

It is highly recommended to only expose VNC to the localhost and connect using a secure connection using SSH or VPN.

TigerVNC Limitations

Multiple X sessions for a single user are not supported
TigerVNC - ArchWiki

This effectively means - if you are logged onto the physical display :0 then you cannot connect a vnc session. If you try to do so, using the same username, a black screen or system lockup will be the likely result.

In that regard it works like Microsoft RDP which logout the physical session when you initiate a remote connection and vice-versa.

The goal

Our goal is to connect to the physical display :0 using VNC.


The remote system will act like a string puppet - you will be able to watch what happens on the remote system and so will anyone else knowing the password or - in case of an attached, powered-on monitor - watching the screen or display.

It will not be possible to share clipboard between systems.

The system to be controlled

On the system to be controlled install package tigervnc and switch to root context

su -l root

VNC password

Create a password for the root user


System service definition

Create a new service definition - the link uses LightDM as example

LightDM is used for the example below, but it should be possible to adapt it to other display managers by modifying the XAUTHORITY variable.
TigerVNC - ArchWiki

This example uses SDDM - edit the file, paste below content and save.

touch /etc/systemd/system/x0vncserver.service

Description=Remote desktop service (VNC) for :0 display SDDM
After=syslog.target network-online.target display-manager.service

# This is for SDDM only
# - as sddm uses a random name for the XAUTHORITY file
ExecStartPre=/usr/bin/bash -c "/usr/bin/systemctl set-environment XAUTHORITY=$(find /var/run/sddm/ -type f)"
ExecStart=x0vncserver -display :0 -rfbauth /root/.vnc/passwd


Enable and start the service

systemctl enable --now x0vncserver.service

Controlling system

Install the package tigervnc and connect

vncviewer ip.x.y.z:5900


Be prepared for weird issues …

For one - after a period of inactivity - the vnc provided view may stop responding - only displaying background or black screen.

While watching the remote screen I was able to activate the password prompt and input the password - yet the vncviewer remainded black with only the mousepointer visible and still controlling the remote as could be seen on the attached monitor.

Connecting directly to screen :0 may seem the way to go if you want to the display manager directly but poses other challenges.

Perhaps you are better of using the configuration outlined in these topics


Mr Danish linux guru ( @linux-aarhus ) is not accepting messages so I post it here instead.

I saw you made a “root tip” on my sollution on vnc player, I’m honored. :smiley:

I’m starting to play around with wayland since that seems to become more and more useful even with an Nvidia gpu.

I got wayland working (and can change on the sddm login screen), but since my sddm still seems to run in x11 when I login it switches to another tty (seems to be quite random after I logout and login again, not always on #2)
I saw this Make SDDM itself run on Wayland and I will play around with it but it seems on the answers it won’t log on tty1 anyway (witch is kinda necessary with the method I used, and xorg)

Solution: switch to x11 on SDDM login (pamac install plasma-wayland-session if you don’t see the drop down menu in lower left corner) and the vnc method I use still works.

Maybe you should edit the “considerations” portion to mention this ONLY works on x11.

Keep up the good work! :smiley: