How to Change Hostname on Ubuntu 20.04?

Introduction

Have you ever heard the term "hostname" and wondered what it means? In simple terms, a hostname is the unique name that identifies a device on a network.

It allows other devices to locate and connect to it, making it an essential component of any network setup. Whether you're running a small home network or managing multiple servers in an enterprise environment, understanding how to change the hostname can come in handy.

In this article, we'll explore how to change the hostname on Ubuntu 20.04 – one of the most popular Linux distributions used today. We'll cover two methods: using the command line interface (CLI) and Ubuntu's graphical user interface (GUI).

Checking Current Hostname

In order to change the hostname, you first need to know what the current hostname is. This can be easily checked using the terminal.

Step 1: Open Terminal

To open the terminal, you can press "Ctrl+Alt+T" or search for "Terminal" in the Applications menu. Once opened, you should see a blank screen with a command prompt waiting for your input.

Step 2: Enter Command

Next, enter the following command into the terminal −

hostname

This will display the current hostname of your Ubuntu system. The output should look something like this −

my-hostname

This should also display your current hostname. Now that you know how to check your current hostname, let's move on to changing it!

Changing Hostname via Command Line

Explaining the CLI Method

The command line interface (CLI) method is a quick and efficient way to change the hostname on Ubuntu 20.04. This method involves using a series of commands in the terminal, which can be intimidating for some users who are not familiar with the CLI. However, this process is straightforward and easy to follow if you know the correct commands.

Providing Screenshots and Step-by-Step Instructions

To change the hostname via CLI, open up a terminal window and enter the command

sudo hostnamectl set-hostname [new_hostname] 

Replace [new_hostname] with your desired hostname (without brackets).

You will then need to edit the /etc/hostname file by entering "sudo nano /etc/hostname" into the terminal. This will open up a text editor where you can modify your hostname by typing in your new name, saving it, and closing out of the editor.

Editing /etc/hostname File

To edit the /etc/hostname file directly from CLI, enter "sudo nano /etc/hostname" into your terminal to open up a text editor. Edit your existing hostname or add a new one on its own line.

sudo nano /etc/hostname

Save changes by hitting CTRL + X to exit out of nano editor and typing "yes" when prompted to save changes. Following these steps should allow you to successfully change your Ubuntu 20.04's hostname using only CLI commands in no time!

Changing Hostname via GUI

Ubuntu's graphical user interface provides a user-friendly way to change the hostname without having to use the command line. This method is ideal for users who prefer a more visual approach and are not comfortable with using the terminal.

To begin, click on the "Activities" button on the top left corner of your screen and search for "Settings" in the search bar. Once you have opened "Settings", navigate to "About" which is found on the left side of the window.

Under "Device name", click on "Rename this device". You will then be prompted to enter your administrative password.

After entering it, you will be able to edit your device's hostname. Simply type in your desired hostname and click on "Rename Device" once you're done.

Restarting Network Services

When you change the hostname on Ubuntu 20.04, it's important to restart network services to ensure that the changes are applied correctly. If you don't restart network services, your system may not be able to resolve hostnames properly and you may experience connectivity issues.

Why Restarting Network Services is Important

The hostname is used by many network services to identify your device. After changing the hostname, network services such as SSH, HTTP, and Samba will have the old hostname cached until they are restarted.

This can cause issues with networking and connectivity until they recognize the new hostname. By restarting network services after changing the hostname, you ensure that all applications are using the updated hostname.

Step-by-Step Instructions for Restarting Network Services

To restart network services on Ubuntu 20.04 after changing your hostname −

• Open a terminal window.

• Type in the following command −

sudo systemctl restart systemd-networkd.service.

• Type in your user password when prompted for it.

• The command should return output indicating that the service has been restarted successfully.

You can also use other commands such as sudo service networking restart, but these might not work on all systems due to differences in Ubuntu versions or system configurations. A good way of testing if everything is working properly is by pinging your new hostname from another device or from an online tool such as "ping.eu". If you receive responses from this new IP address then everything should be configured correctly!

Troubleshooting Common Issues

Changing the hostname on Ubuntu 20.04 can sometimes present issues that may need troubleshooting. In this section, we will discuss common issues that users face when changing the hostname and provide troubleshooting tips for each issue.

Conflicts With Existing Hostnames

One of the common issues that may arise when changing the hostname is conflicts with existing hostnames. This can occur if there are multiple devices on a network with the same hostname.

When this happens, it makes it difficult to identify which device you are communicating with. To avoid conflicts with existing hostnames, it's recommended to choose a unique hostname that hasn't been used before.

If you encounter a conflict, try changing the hostname again by adding a number or letter at the end of it to make it unique. Alternatively, you can also check other devices' hostnames on your network and change your name accordingly.

Issues With DNS Resolution

DNS resolution is an essential function in identifying devices on a network by their respective hostnames instead of IP addresses. Changing a device's hostname can cause issues if there is no proper DNS resolution configured.

To troubleshoot DNS-related issues when changing your Ubuntu 20.04 hostname, check if other devices can resolve your new name properly using nslookup or dig commands in terminal mode --- run 'nslookup newhostname' (without quotes) on another machine in your internal network – and check if they get an IP address response from your newly named machine If DNS resolution is not working correctly after changing the hostname on Ubuntu 20.04 machines connected to external networks such as AWS Cloud servers or Azure virtual machines , ensure proper configuration settings for DHCP client settings such as "prepend domain-name-servers" are set correctly in /etc/dhcp/dhclient.conf and network interface files located in /etc/netplan/*.yaml.

If you have manually configured DNS servers, make sure they are still valid after the hostname change. By following these troubleshooting tips, users can easily avoid and fix common issues that may arise when changing the hostname on Ubuntu 20.04.

Conclusion

Changing the hostname on Ubuntu 20.04 is a simple but important task. The hostname is what identifies your device on a network, and changing it can help avoid conflicts and improve network security.

We covered two ways to change the hostname, via command line or GUI, and discussed the importance of restarting network services after making changes. We also provided troubleshooting tips for common issues that may arise during the process.

Now that you have learned how to change your hostname on Ubuntu 20.04, you can confidently manage your device's network identity with ease. Remember to choose a unique and descriptive hostname that follows best practices for naming conventions.