The following commands will assist you with network restart procedure on Ubuntu 16.04 Xenial Xerus Linux. We will start with the most recommended commands and move down to more obscure or obsolete commands in case the above commands will fail from some reason. Let's begin with system and service manager by using systemctl command to restart network service:
$ sudo systemctl restart NetworkManager.service
Next command service will restart a relevant networking System V init script:
$ sudo service network-manager restart
The following command nmcli is a command-line tool for controlling NetworkManager which will restart the Network Manager directly:
$ sudo nmcli networking off $ sudo nmcli networking on
The old fashion way using System V init scripts directly is still available on Ubuntu 16.04 Xenial Xerus Linux:
$ sudo /etc/init.d/networking restart OR $ sudo /etc/init.d/network-manager restart
In the last example we will restart the netowrk interface directly using ifup and ifdown commands. Note the -a option instructs ifup and ifdown commands to restart all available network interfaces marked "auto":
$ sudo ifdown -a $ sudo ifup -a