Hi, @sebbyv , and welcome to the community!
As a new user stick to cockpit GUI . The old server-manager is no longer needed to manage the server other than as a requirement for samba-audit IIRC, and in some specific cases it can be used to do some tricks.
On the current server-manager GUI (cockpit, port 9090) you can restrict access by IP, 2FA, and network zone (for instance access from green only), at least (plus grant access to some parts of the server-manager to specific users/groups IIRC).
You can restrict access to the old server-manager (NethUI or NethGUI, port 980) by network zone but if you do not need it, you can uninstall
nethserver-httpd-admin (IIRC it is needed to view the reports from samba audit if you are using that module).
Even if you restrict access to green zone only, you can use ssh tunneling (port forwarding) to manage it from outside.
Another way that doesn’t require removal is to disable the related services.
- For the old server-manger:
systemctl disable --now httpd-admin
- For cockpit server-manager:
systemctl disable --now cockpit cockpit.socket
…but you will need to enable them when you want to use them, and possibly disable them again after their related packages are updated.