In CentOS/RHEL 8 the network services scripts are not presented anymore(systemctl start network.service or /etc/init.d/network script). In order to restart the network services follow one of these two options.
Using Network Manager
Use the systemctl command to restart the NetworkManager service/target as shown below:
# systemctl restart NetworkManager
Using nmcli Tool
Note: Run these commands from the GUI or the console, as the network will disable.
# nmcli networking off # nmcli networking on
In case it is needed to run from the terminal from an ssh session, can be run it like this:
# nmcli networking off; nmcli networking on