Configuring IP address on Ubuntu server without using any tools other than a text editor

The new interfaces configuration file now lives in the /etc/netplan directory. There are two renderers: NetworkManager and networkd.

NetworkManager renderer is mostly used on desktop computers and networkd on servers. If you want NetworkManager to control the network interfaces, use NetworkManager as the renderer, otherwise use networkd.

When you use NetworkManager as the renderer, you will use the NetworkManager GUI to manage the interfaces.

DHCP sample file using networkd

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
 version: 2
 renderer: networkd
 ethernets:
   ens33:
     dhcp4: yes
     dhcp6: yes

Static configuration

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
 version: 2
 renderer: networkd
 ethernets:
   ens33:
     dhcp4: no
     dhcp6: no
     addresses: [192.168.1.2/24]
     gateway4: 192.168.1.1
     nameservers:
       addresses: [8.8.8.8,8.8.4.4]

Apply changes

sudo netplan apply

Multiple IP addresses and multiple gateways

 
network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s0:
     addresses:
       - 9.0.0.9/24
       - 10.0.0.10/24
       - 11.0.0.11/24
     #gateway4:    # unset, since we configure routes below
     routes:
       - to: 0.0.0.0/0
         via: 9.0.0.1
         metric: 100
       - to: 0.0.0.0/0
         via: 10.0.0.1
         metric: 100
       - to: 0.0.0.0/0
         via: 11.0.0.1
         metric: 100

Wireless

 
network:
  version: 2
  renderer: networkd
  wifis:
    wlp2s0b1:
      dhcp4: no
      dhcp6: no
      addresses: [192.168.0.21/24]
      gateway4: 192.168.0.1
      nameservers:
        addresses: [192.168.0.1, 8.8.8.8]
      access-points:
        "network_ssid_name":
          password: "**********"

Static

 
network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s0:
      addresses:
        - 10.10.10.2/24
      gateway4: 10.10.10.1
      nameservers:
          search: [mydomain, otherdomain]
          addresses: [10.10.10.1, 1.1.1.1]

Edit network configuration file

sudo vim /etc/network/interfaces

You fill find configuration something like this

# The primary network interface -- use DHCP to find our address
auto eth0
iface eth0 inet dhcp

Change it to this

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.1.2
gateway 192.168.1.1
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
dns-nameservers 8.8.8.8 8.8.4.4

And finally restart networking service

sudo /etc/init.d/networking restart

You should be able to ping the host on the new IP address

If you need to add static routes, you can do it here by adding the lines

up route add -net 192.168.10.0 netmask 255.255.255.0 gw 192.168.180.1 dev eth0

And delete them

down route del -net 192.168.10.0 netmask 255.255.255.0 gw 192.168.180.1 dev eth0