What Is the Hosts file?
The “/etc/hosts” file is where your system keeps an internal map of IP Addresses -> hostnames. This doesn’t require a DNS server because it’s stored locally on your machine. This is a great way to manage things like internal servers or other devices on your network that commonly require you to enter an IP Address. I use this all the time for Raspberry Pi projects and managing commonly-used KVM Virtual Machines.
How Do I Use the Hosts File?
First, take a look at what’s already in the hosts file. Type the following command into the terminal and press enter: In the output, you’ll find two IP addresses that are meant for your local machine to identify itself. If you run the ping localhost command, you’ll see one of these IP addresses come up. That’s because Linux automatically generates these two entries into the hosts file. If you want to add more entries, all you have to do is follow the formatting of the file, and you’ll be all set to go.
Editing the Hosts File
To edit the hosts file, just open it in your preferred text editor. You can use Vim, Nano, Gedit, Kate, or whichever you like best. You should see the content in the following format: So if I have a Pi Hole server with an IP address of 192.168.122.7, my format would be something like this: It’s, of course, dependent on what you want to name it. That means that any time you want to address that Pi Hole server, whether it’s via ping, ssh, or some other tool, you don’t have to enter the IP address. You can just type pihole.local into the terminal. It’s quite the timesaver, especially if you get to shorter server hostnames. It’s also important to note that you don’t have to use “.com,” “.net,” or “.org” addresses. You can even just call it pihole, and your system will recognize it. I used a .local address to show you the “proper” way to do it, but you can call them server if it’s your only one. It’s also useful for virtual machines on a virtualization server or workstation. Remembering VM IP addresses is a huge pain, and using the hosts file is perfect to manage that. With my VM IP Address, 192.168.122.202, I’ll take that and edit my hosts file with this: Then I can ping that VM with the hostname, which makes it much easier to remember what I’m looking for. You can see that rather than an IP address, I’m pinging the hostname, and that shows up in the output of the command. The system has an internal map of that IP and hostname, so it’s easy to slot into that spot.
Wrapping Up
As you can see, learning how to edit the Hosts file in Linux can be a useful skill, as it allows you to save you a lot of time later down the line. If you are on Windows, you can also edit the Hosts file and use it exactly the same way as stated above.
