How to set a Static IP address on Ubuntu 20.04?

A server usually always has a static IP address that facilitates the rest of the network services. So although it is not mandatory if it is of great help for the management of the server. So this post is about how to define a static IP address in Ubuntu 20.04

A Static IP address

An IP address is an identifier held by each device that connects to the Internet or a computer network. In the case of the Internet, it must be unique to avoid connection conflicts.

On the one hand, there are dynamic IP addresses that change their value from time to time. Normally, these addresses are assigned by a DCHP server. The sysadmin does not have to worry about the assigned address as they are renewed from time to time.

On the other hand, we have static or fixed IP addresses, which unlike dynamical ones, do not change over time. In this case, it must be assigned and configured manually in the system.

Each of them has its own advantages, however, for internal networks, it is convenient to have equipment with static IP addresses. This facilitates the administration and routing of packets within the network. It is also easier to maintain the network.

So, let us work!

How to set up a static IP address on Ubuntu 20.04?

Before starting the work, it is necessary to know which is the network interface to which we want to assign the static IP address. To do this, execute the following command:

:~$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 08:00:27:80:31:48 brd ff:ff:ff:ff:ff:ff
    inet 192.168.250.8/16 brd 192.168.255.255 scope global dynamic enp0s3
       valid_lft 86204sec preferred_lft 86204sec
    inet6 fdd4:a148:ea1:7a00:a00:27ff:fe80:3148/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 7006sec preferred_lft 3406sec
    inet6 fe80::a00:27ff:fe80:3148/64 scope link 
       valid_lft forever preferred_lft forever

As you can see in the image, I only have a network interface called enp0s3 whose IP address is 192.168.250.8 but it was assigned with DHCP. So I’m going to assign it the static IP address 192.168.250.20

In Ubuntu the network configuration is done by netplan where the configurations are written in yml format.

So, before modifying the configuration file, it is convenient to make a backup of this file to prevent problems.

:~$ sudo cp /etc/netplan/00-installer-config.yaml /etc/netplan/00-installer-config.yaml.bak

And now you can modify the file with the help of nano.

:~$ sudo nano /etc/netplan/00-installer-config.yaml

You will see the following content:

network:
  ethernets:
    enp0s3:
      dhcp4: true
  version: 2

Then modify it to look like this:

dhcp4: no
      addresses:
        - 192.168.121.199/24
      gateway4: 192.168.121.1
      nameservers:
          addresses: [8.8.8.8, 1.1.1.1]

I think the options are very easy to understand but I will explain it to you anyway:

• dhcp4: it is not so that the interface does not use DHCP and only uses the IP address we set.
• addresses: The IP address that we are going to define.
• gateway4: The gateway of the network
• nameservers: the DNS servers that the computer will use.

Then save the changes and close the file. Remember that the file is in yml format so it respects the rules and syntax so it does not give any error.

To apply the changes, execute the following command:

:~$ sudo netplan apply

And check the changes with the following command:

:~$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 08:00:27:80:31:48 brd ff:ff:ff:ff:ff:ff
    inet 192.168.250.20/16 brd 192.168.255.255 scope global enp0s3
       valid_lft forever preferred_lft forever
    inet6 fdd4:a148:ea1:7a00:a00:27ff:fe80:3148/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 7148sec preferred_lft 3548sec
    inet6 fe80::a00:27ff:fe80:3148/64 scope link 
       valid_lft forever preferred_lft forever

As you can see, everything went well.

Conclusion

Setting a static IP address to Ubuntu 20.04 is quite simple even from the terminal. With this you will be able to manage your server or computer within a network more easily.

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