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Ubuntu 18.04 Server - Set Static IP With Netplan

networking Netplan

Netplan is the new networking system that is taking over from editing the /etc/networking/interfaces file. The most common thing you will want to do is set a static IP. You can do that by simply editing the /etc/netplan/01-netcfg.yaml file.

sudo vim /etc/netplan/01-netcfg.yaml

The file will look like below:

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  ethernets:
    ens2:
      dhcp4: yes

Here is an example configuration to set a static IP of 192.168.1.100 with your router/gateway being at 192.168.1.1 and wanting to use OpenDNS dns servers:

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  ethernets:
    ens2:
        addresses:
            - 192.168.1.100/24
        gateway4: 192.168.1.1
        nameservers:
            addresses:
                - 208.67.222.222
                - 208.67.220.220

The CIDR needs to reflect your network's subnet's netmask (useful lookup table). It is not the CIDR for IPs you allocate to the server (e.g. don't use /32) See the appendix if you want the PHP code for generating such a config.

Before I could paste, I had to fix an "issue" with vim first with the following commands:

echo "set mouse=" > .vimrc
sudo echo "set mouse=" | sudo tee -a /root/.vimrc Ubuntu Blog - Ubuntu Bionic: Netplan

Once you have successfully edited your configuration file, you can apply it with:

sudo netplan apply

Now your server should be using the new IP.

Testing Configuration Before Applying

The following command will check the changes before applying them and waiting for 2 minutes. During this time, one can press enter/return on the keyboard to keep the changes. If one does not do this then the changes are reverted. This is particularly useful in case you mess up your network, and can't send any SSH commands to undo what you have just done.

sudo netplan try

Extra Info

Netplan is actually pretty powerful and you can split your configuration up across multiple files in multiple locations as well as configuring bridges/bonding etc. I recommend reading these two posts for more information:

DHCP With Manually Set DNS Nameservers

If you want to use DHCP for setting your IP address, but you prefer to manually set your DNS nameserver, then you would do something like below:

network:
  version: 2
  renderer: networkd
  ethernets:
    ens18:
      dhcp4: true
      dhcp4-overrides:
        use-dns: no
      nameservers:
        addresses:
          - 192.168.0.222

The above example assumes your nameserver is at 192.168.0.222.

Appendix

PHP Code To Generate Static IP YAML File

<?php

$interfaceName = "enp1s0";
$staticIp = "192.168.0.3";
$cidr = 16;
$gateway = "192.168.0.1";
$nameserverIps = array("8.8.8.8", "8.8.4.4");

$networkConfig = array(
    'network' => array(
        "version" => "2",
        "renderer" => "networkd",
        "ethernets" => array(
            $interfaceName => array(
                "addresses" => array(
                    "{$staticIp}/{$cidr}",
                ),
                "gateway4" => "$gateway",
                "nameservers" => array(
                    "addresses" => $nameserverIps,
                ),
            ),
        ),
    ),
);

print yaml_emit($networkConfig) . PHP_EOL;

References

Last updated: 27th August 2022
First published: 16th August 2018