Configure Network Settings on Ubuntu (Network Manager, Systemd and Netplan)

How to Use Network Manager on Ubuntu?

Ubuntu’s default network management tool is Network Manager. This is a universal way to configure a network for Ubuntu desktops. NM includes a graphical and nmcli command, allowing you to conveniently work with WLAN connections, VLAN, etc.

Check that this service is running:

$ systemctl status NetworkManager

The Network Manager configuration file is /etc/NetworkManager. Connection settings are stored in the system-connections directory. To configure the network parameters, you can use the nmcl command or the pseudo-graphical interface of the Network Manager TUI.

$ sudo nmtui

List network interfaces:

$ nmcli device

List all interface network settings:

$ nmcli

Specific network interface settings:

$ nmcli device show ens33

Use nmcli to configure a static IP address for the interface:

$ sudo nmcli con mod ens33 ipv4.addresses 192.168.55.140/24
$ sudo nmcli con mod ens33 ipv4.gateway 192.168.55.1
$ sudo nmcli con mod ens33 ipv4.dns "8.8.8.8"

Apply network settings:

$ nmcli con up ens33

Enable/disable interface:

$ nmcli connection down my_ethernet

Ubuntu Network Configuration with systemd-networkd

With systemd, you can use the systemd-networkd service to configure your network settings. It is lighter and faster than Network Manager and is recommended for use on Ubuntu servers.

First, disable applying network settings from the /etc/network/interfaces file. Just rename the file:

$ sudo mv /etc/network/interfaces /etc/network/interfaces.save

The /etc/systemd/network directory contains the systemd-networkd.service configuration files.

Here you can create one of three file types:

• *.link – sets interface physical settings (name, MAC, MTU, etc.)
• *.network – network settings (DHCP/static IP, MAC, MTU, routes, DNS)
• *.netdev – configure virtual interfaces (VLAN, bridges, tunnels, VPN, etc.)

Example configuration file for the eth0 interface to get network settings from the DHCP server:

$ sudo mcedit /etc/systemd/network/mylan.network

[Match]
Name=eth0
[Network]
DHCP=ipv4
LinkLocalAddressing=no

If the host has more than one network interface, you can specify eth* here.

Static IP configuration example:

[Match]
Name=enp8s0
[Network]
Description=Local network
Address=192.168.55.25/24
Gateway=192.168.55.1
DNS=192.168.55.1 192.168.155.1
Domains=poweradm.com
LinkLocalAddressing=no

Enable the systemd-networkd service:

$ sudo systemctl enable systemd-networkd.service
$ sudo systemctl start systemd-networkd

Check network interface status:

$ networkctl list

List network settings:

$ networkctl status

Check the systemd-networkd log:

$ journalctl -u systemd-networkd.service

Configuring Networking on Ubuntu with Netplan

Netplan adds a new layer of abstraction on top of the Ubuntu network manager. The configuration files can be found in the /etc/netplan directory.

Ubuntu Desktop has the following default config file:

$ cat /etc/netplan/01-network-manager-all.yaml

# Let NetworkManager manage all devices on this system
network:
  version: 2
  renderer: NetworkManager

The renderer: NetworkManager directive specifies that Network Manager is used to manage the network.

To obtain the network settings from the DHCP server for the enp0s3 interface, use the configuration:

network:
  version: 2
  renderer: networkd
  ethernets:
    enp0s3:
      dhcp4: yes

Set static IP address:

network:
  version: 2
  renderer: networkd
  ethernets:
    enp0s3:
      dhcp4: no
      addresses: [192.168.1.10/24]
      gateway4: 192.168.1.1
      nameservers:
        addresses: [8.8.8.8, 8.8.4.4]

Netplan allows you to check the network settings before applying them:

$ sudo netplan try

Apply new network configuration:

$ sudo netplan apply

Using /etc/network/interfaces Configuration on Ubuntu

The classic way to configure network settings in Ubuntu is to use the /etc/network/interfaces file.

In the easiest case, if you want to get all your network settings from DHCP, you need to set this here:

iface lo inet loopback
auto eth0
iface eth0 inet dhcp

• iface – network interface name
• inet–IPv4 protocol
• lo – loopback interface
• auto eth0 – enable interface on boot

If you need to set a static IP:

iface lo inet loopback 
auto eth0
iface eth0 inet static
address 192.168.55.100 
netmask 255.255.255.0 
gateway 192.168.55.1
dns-nameservers 8.8.8.8 8.8.4.4

You must restart the service after making the changes:

$ sudo systemctl restart networking.service

Use the ifup and ifdown commands to enable/disable the network interface:

$ sudo ifdown enp7s0
$ sudo ifup enp7s0