About elevation of privilege from the first user creation

When installing Ubuntu 22.04.1 LTS with gnome interface, it's asked to create a first user, and we can't override it.

This user account is local to the machine, I don't want to communicate this account to the end user of the machine, because I want this account to be used only for administration by the IT department.

So this machine is joined to the domain, and it's the domain account of the user who must be sudoers of the machine, I added it well in the sudoers file.

When I'm in the terminal, I don't have any concerns about elevation of privilege, the user's domain account is requested.

On the other hand, in the graphical interface, if I want to configure the VPN or install an application, it's the locauser account that is requested !

I don't understand how this works. Do you have an idea?

I finally found the solution faster than I thought here :

About Ubuntu Prompt System Policy Prevents Modification of Network Settings for All Users

https://unix.stackexchange.com/questions/534469/system-policy-prevents-control-of-network-connections

This solution work :

Create a file named universal.pkla in the /etc/polkit-1/localauthority/50-local.d folder with these contents:

    [Allow access to anything for remote users]
    Identity=unix-user:*
    Action=*
    ResultAny=yes
    ResultInactive=yes
    ResultActive=yes

Then restart polkit with "sudo systemctl restart polkit.service" or reboot. I haven't seen any polkit authentication prompts since.

Thanks !