Setup Network Device on Ubuntu 18.04
To setup a network device on Ubuntu server 18.04, we need to use new network setup application netplan. Netplan allow us to configure new network adapter.
We encounter network setup issue when we need to add a second network adapter in VirtualBox for networking with host.
Using Ip LinkBefore we use netplan, we can use the following command to show all device:
ip link show
To temporary enable the device we can use the command below: (please replace eth0 with the network device that you want to configure):
sudo ip link set eth0 up
Use the following command to enable dhcp client.
sudo dhclient eth0
To enable the network adapter permanently, we need to configure netplan. Use the following command to open the configuration file:
sudo nano /etc/netplan/50-cloud-init.yaml
On the configuration file, we add additional network device as follows. Please note that enp0s2 is the current default device and enp0s4 is the new device. Please also make sure that indentation are aligned correctly. This configuration file requires proper indentation.
network: ethernets: enp0s2: addresses:  dhcp4: true enp0s4: addresses:  dhcp4: true version: 2
To test if the network setting is correct, use the following command:
sudo netplan try
If the test is successful, we can apply the setting using the command:
sudo netplan apply