Restart Ubuntu or Debian Network

Ubuntu 20.04

systemctl restart systemd-networkd.service

Note that Ubuntu 20.04 is using ‘/etc/netplan/’, different from Debian which is using ‘/etc/network/’.

If above does not work

service network-manager restart

or

systemctl restart NetworkManager.service

Debian

/etc/init.d/networking restart
 
#for stop, use: stop
#for start use: start