VNC connection timeout when monitor is detached

Rocky Linux General
1

I’ve set up many Linux systems that allow VNC without needing the monitor to remain attached once it’s built (i.e. headless). I’ve just set up a Rocky Linux 9 system with RealVNC and gotten that to work with the monitor attached. However, if I pull the monitor off, the VNC client fails to connect with a timeout error. I’ve tried 1) just pulling the HDMI connection, and 2) shutting the system down before detaching the monitor.

For the second method (the shutdown and detach) I see vncserver virtuald, x11-serviced, and x11-core services running once I’ve restarted the server. But the vnc client times out trying to connect.

Any thoughts? I really don’t want to have a monitor attached to this server, I’m using it as a VM host.

2

The solution was to rebuild the system and use tigervnc instead of realvnc.

3

Hi, I am a newbie trying to set up tigervnc on Rocky Linux 9, can you share the details of how to configure (securely)? To be specific, I have done the following:
# dnf install tigervnc tigervnc-server
# su - username
username> vncpasswd

Now I should create the file /etc/systemd/system/vncserver@<something here?>.service, but the default file I find in /lib/systemd/system/vncserver@.service is different - has different entries under [Service] than what is written in an online HowTo https://www.answertopia.com/rocky-linux/rocky-linux-remote-desktop-access-with-vnc/

I don’t think the answertopia HowTo is correct because it says to open a port in the firewall but I didn’t think I have to do that if vncserver runs as a service. Also opening port 5901 is also not in the RedHat 9 documentation, although this says nothing about the contents of /etc/systemd/system/vncserver@.service:

So any help is greatly appreciated!

4

Solved my problem: follow the RedHat instructions, don’t open ports, don’t create any files /etc/systemd/system/vncserver@.service in fact remove any such files that exist. Simply edit the /etc/tigervnc/vncserver-config-defaults:
session=gnome
alwaysshared
securitytypes=vncauth,tlsvnc
geometry=2560x1440

and the /etc/tigervnc/vncserver.users file:
:2=username

then DON’T run the following, because I’m connecting through SSH:
DON’T [root]# firewall-cmd --permanent --add-service=vnc-server
DON’T [root]# firewall-cmd --reload
Since I had previously set vncpasswd and failed, restore SE Linux context just in case:
[username]$ restorecon -RFv ~/.vnc
Start vnc server for user:
[root]# systemctl enable --now vncserver@:2
Since I use NVIDIA drivers, edit [daemon] section of /etc/gdm/custom.conf:
DefaultSession=gnome-xorg.desktop
WaylandEnable=False
Then reboot:
[root]# reboot

To login securely from Windows 10 box, set up ssh tunnel in cmd window:
ssh -L 5900:127.0.0.1:5902 username@remote-ipaddress

Now point Win10 VNC client (e.g. TigerVNC) to 127.0.0.1:5900, enter VNC passwd, get user login! Trying the same with remote-ipaddress:5902 fails to connect, good.

5