I'm comparing Centos7 and Rhel 7.2 installations.rhel/centos installer creates simple network-scripts for existing adapters. They don't start automatically. NetworkManager sees them with names enp0s*.On Centos it's enough to delete the network scripts created by the installer to make NM create and activate in-memory connections with dhcp:rm -f /etc/sysconfig/network-scripts/ifcfg-enp*After reboot the connections appear in nmtui as Wired connection n and activate.But on Rhel I don't see them in nmtui after deleting the scripts. The list is empty.Why do I need this? Because it's a virtual machine and adapter names may change when I move it to another host.
NetworkManager not creating in-memory connections
rhel;networkmanager
When NetworkManager starts and finds no connection for a device it might create an in-memory connection as you saw. The no-auto-default configuration disables that behavior. See 'man NetworkManager.conf'. Probably you have that configuration in place. Note there is also a package NetworkManager-config-server which provides such a configuration. Maybe you have it installed?Note that NM creates these auto-default connections so that you can start it on a system without configuration and it would activate your network. Usually you don't use this on regular systems and instead you configure a persistent connection. If you modify the connection it becomes persistent and store to disk.If you say that your device names might change, in that case you should instead unset connection.interface-name so that this connection applies to any device. See 'man nm-settings'.And if you were unhappy with the connection from the installer, you could just modify it instead of deleting it (nmcli connection modify $name connection.auto-connect yes).