The gateway address (also known as the "default gateway") is a crucial address configured on your computer, without which you wouldn't be able to get much done. This address acts as a sort of bridge between your local network and the internet. Although the gateway address is capable of much more than bridging the internal with the external, we'll stick with that definition, as it's how the majority of people need it to function.

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Let's imagine your local area network (LAN -- the network within your home or business) is a castle, and around that castle is a moat filled with acid. If you dive into that moat... you're dead. Since Amazon doesn't deliver to your castle (thanks to that flesh-melting moat), you need a way to get to the outside world, where things happen.

To solve the problem, you build a bridge that gives your castle access to the world beyond your moat. That bridge is the default gateway.

How is the default gateway assigned?

The ISP you use most likely sent you a modem/router. Once that device is plugged in and ready, it'll start assigning addresses via DHCP. Included with an IP address, your computer will also automatically be assigned DNS addresses and a default gateway.

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Most often, this happens seamlessly and without problems. I have, on occasion, run into an issue with a piece of software (be it something for a server or a desktop) where the application decided to assign a default gateway and guessed wrong. With an incorrect gateway address, the app in question wasn't able to access the internet, so it wouldn't function.

Why does this happen?

It's actually fairly simple.

Most ISPs set the default gateway address for DHCP assignment to 192.168.1.1. That address is then handed out and configured by all networkable devices on the LAN. That 192.168.1.1 address is fairly common, but it's not the only one in use. For example, when I was with Comcast, the default gateway was 192.168.1.1. However, when I switched to AT&T fiber, the gateway address was 192.168.1.254.

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I've had some applications that assumed the gateway was 192.168.1.1, and I had to reconfigure them to use the proper address. I've also installed a Linux distribution or two (as a virtual machine) and found that they also decided to use the wrong address.

Fortunately, with Linux, setting the default gateway address can be done via a GUI or the command line.

I'm going to show you how to change the default gateway via a GUI (demonstrating with Pop!_OS) and then via the command line.

Let's get to work.

How to change the default gateway via a GUI

What you'll need: The only things you'll need for this are a running instance of Linux and a user with sudo privileges. As I mentioned, I'll demonstrate this on Pop!_OS (which is currently still based on GNOME). If you use a different desktop environment, the process should be similar.

ip a

How to change the default gateway via the command line

This method is actually easier than the one above and will work with any Linux distribution. Let's say the correct default gateway address is 192.168.1.254. How do we configure this?

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1. Locate the name of your ethernet device

First, you must locate the name of your ethernet device. This is done with the command:

ip a

You should see a listing that is something like wlp15s0. Whatever is associated with your desktop's IP address is the name of the device to be used.

2. Change the default gateway

Let's use the above example as the device name to configure the proper 192.168.1.254 gateway address. This is done with the command:

sudo ip route | grep defaultchange default via 192.168.1.254 dev wlp15s0

The above command will change the default gateway on device wlp15s0 to 192.168.1.254. You can test it by running the command:

ip route | grep default

You should see 192.168.1.254 listed.

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Congratulations, you've just changed your default gateway on Linux.

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• The open-source tools that could disrupt the entire IT incident management market
• This Linux distro could let your old laptop 'shine on' after Windows 10's sunset
• 6 Linux myths, busted
• 5 lightweight Linux distributions with very low system requirements