Setting a Static IP in Ubuntu

Nmcliis the command-line network manager tool, and can be used to change your IP address, configure network devices, and — relevant to our purposes — set up a static IP in Ubuntu.

Let’s take a look at the network connections that already exist on the computer. We’re using the connection command with the show argument.

nmcli connection show

This displays some information about each connection. We only have a single connection configured.

The output is wider than the terminal window. This is the information that we’re shown. 

NAME           UUID                                 TYPE     DEVICE 
netplan-enp0s3 1eef7e45-3b9d-3043-bee3-fc5925c90273 ethernet enp0s3

• Name: Our network connection is called “netplan-enp0s3.”
• UUID: The universally unique identifier Linux uses to reference this connection internally.
• Type: This is an ethernet connection.
• Device: This connection is using the “enp0s3” network interface. It’s the only network card in this computer.

We can use the ip command to discover the IP address this computer is using.

ip addr

In the output we can see the “enp0s3” entry, and its current IP address, 192.168.86.117. The “/24” is a shorthand way of saying that this network uses a 255.255.255.0 subnet mask. Take a note of this number, we’ll need to use it later.

We need to choose the IP address we’re going to set as our static IP address. Obviously, you can’t use an IP address that is already in use by another device. One safe way to proceed is to use the current IP address assigned to the Ubuntu system. We know for certain that nothing else is using that IP address.

If we want to use a different IP address, try pinging it. We’re going to test whether IP address 192.168.86.128 is in use. If everything else on your network uses DHCP and you get no response to the ping command, it should be safe to use.

ping 192.168.86.128

Even if another device had previously used that IP address, it’ll be given a new IP address when it next boots up. Nothing responds to the ping requests, so we’re clear to go ahead and configure 192.168.86.128 as our new static IP.

We also need to know the IP address of your default gateway, which will usually be your broadband router. We can find this using the ip command and the route option, which we can abbreviate to “r.”

ip r

The entry that starts with “default” is the route to the default gateway. Its IP address is 192.168.86.1. Now we can start to issue commands to set up our static IP address.

The first command is a long one.

sudo nmcli con add con-name "static-ip" ifname enp0s3 type ethernet ip4 192.168.86.128/24 gw4 192.168.86.1

Taken in small chunks, it’s not as bad as it looks. We’re using sudo. The nmcli arguments are:

• con: Short for “connection.”
• add: We’re going to add a connection.
• con-name “static-ip”: The name of our new connection will be “static-ip.”
• ifname enp0s3: The connection will use network interface “enp0s3.”
• type ethernet: We’re creating an ethernet connection.
• ip4 192.168.86.128/24: The IP address and subnet mask in classless inter-domain routing notation. This is where you need to use the number you took note of earlier.
• gw4 192.168.86.1: The IP address of the gateway we want this connection to use.

To make our connection a functioning connection, we need to provide a few more details. Our connection exists now, so we’re not adding anything, we’re modifying settings, so we use the mod argument. The setting we’re changing is the IPv4 DNS settings. 8.8.8.8 is the IP address of Google’s primary public DNS server, and 8.8.4.4 is Google’s fallback DNS server.

Note that there is a “v” in “ipv4.” In the previous command the syntax was “ip4” without a “v.” The “v” needs to be used when you’re modifying settings, but not when adding connections.

nmcli con mod "static-ip" ipv4.dns "8.8.8.8,8.8.4.4"

To make our IP address static, we need to change the method which the IP address obtains its value. The default is “auto” which is the setting for DHCP. We need to set it to “manual.”

nmcli con mod "static-ip" ipv4.method manual

And now we can start or “bring up” our new connection.

nmcli con up "static-ip" ifname enp0s3

We didn’t get any error messages which is great. Lets use nmcli to look at our connections once more.

nmcli con show

Here’s the output:

NAME           UUID                                 TYPE     DEVICE 
static-ip      da681e18-ce9c-4456-967b-63a59c493374 ethernet enp0s3 
netplan-enp0s3 1eef7e45-3b9d-3043-bee3-fc5925c90273 ethernet --

Our static-ip connection is active and using device “enp0s3.” The existing connection “netplan-enp0s3” is no longer associated with a physical network interface because we’ve pinched “enp0s3” from it.

Click the icons at the far-right end of the system bar to show the system menu, then click on the “Wired Connected” menu option. If you’re using a wireless connection, instead click the name of your Wi-Fi network.

The available connections are displayed. A dot indicates which is in use.  Click the “Wired Settings” or “Wi-Fi Settings” menu option. The details of the active connection are displayed.

To create a new connection using the “Settings” application, click the “+” icon on the “Networks” page, above the list of wired connections.

A dialog appears. We need to provide a name for our new static IP connection.

We’re calling our new connection “static-2.” Click the “IPv4” tab.

Select the “Manual” radio button, and complete the “Address”, “Netmask”, and “Gateway” fields. Also complete the DNS field, and then click the green “Apply” button. Note the comma between the DNS entries.

Our new connection is listed in the “Wired” connections pane.

You can swap between the available connections by clicking directly on their names.

If you want to modify a connection after you create it, click the cog icon. In this case, we’ll enter the settings for the “static-ip” connection.

A dialog box opens. Click on the “IPv4” tab.

Because we set our new IP address to be static, the “Manual” radio button is selected. You could change this back to DHCP by selecting the “Automatic (DHCP)” radio button, and clicking the green “Apply” button.