Config Network on Ubuntu Server

NetPlan Files

Network interfaces in Ubuntu 20.04 are configured in NetPlan YAML files, which are stored under /etc/netplan. The default file networking interfaces for a new Ubuntu 20.04 install is /etc/netplan/00-installer-config.yaml.

To edit the default netplan file, use the following command.

    sudo vi /etc/netplan/00-installer-config.yaml

Alternatively, a simpler text editor by the name of nano can be used instead of vim.

    sudo nano /etc/netplan/00-install-config.yaml

How to Set Static IP Address

The following is an example Netplan file with a network interface that has a static IP address. The interface's name is en01 and it has been assigned static IP addresses 192.168.1.25/24 for IPv4, and 2001:1::1/64 for IPv6.

As both IPv4 and IPv6 have been assigned static IP addresses, each has a gateway set too.

DNS Name servers are also defined in this file. We'll cover DNS a little further down in this tutorial.

network:
  version: 2
  renderer: networkd
  ethernets:
    en01:
      addresses:
      - 192.168.1.25/24
      - "2001:1::1/64"
      gateway4: 192.168.1.1
      gateway6: "2001:1::2"
      nameservers:
        addresses:
        - 8.8.8.8
        - 8.8.4.4

To apply changes to netplan you will need to reload your Netplan network configurations.

sudo netplan apply

The following example shows how to enable DHCP for both IPv4 and IPv6. To enabled just one, you would remove the network IP version not needed.

network:
  version: 2
  renderer: networkd
  ethernets:
    en01:
      dhcp4: true
      dhcp6: true

sudo netplan apply

How to Set DNS

The following is an example of a network interface id0 with nameservers configured.

ethernets:
  en01:
    [...]
    nameservers:
      search: [lab, home]
      addresses: [8.8.8.8, "FEDC::1"]

• search is a list of search domains, which are used when a non-fully qualified hostname is given. For example, if you were to ping server1 rather than server1.lab.

• addresses is a list of IPv4 or IPv6 ip addresses for the DNS name servers. IPv6 must be quoted.

How to set WiFi Authentication

ethernets:
  id0:
    [...]
    access-points:
      mode: infrastructure
      bssid: mywifi
      band: 5GHz
      channel: 5
    auth:
      key-management: none | psk | eap 
      password: my-password-string

• mode set the mode type for your wifi network interface. For connecting to access points the value should be set to infrastructure, which is the default.

• bassid is the name of your wifi connection, as configured on your access point.

• band is used to set the wireless band. It accepts two values: 5GHz and 2.4GHz. If left unset, the wifi endpoint and your network device will automatically establish the best band. By setting this value you will * force the connection to use a specific band.

• channel is used to set your wifi channel, and only takes affect if the band property is set.

• WPA and EAP connection modes accept the following configurations.

• key-management sets how the supported key management mode.

• none to disable key management

• psk for WPA with pre-shared key, common for home wifi.

• eap for WPA with EAP, which is common for enterprise wifi networks.

• password sets the pre-shared key or password for your wifi network, when the mode is set to either psk or eap.