How to Change Hostname in Debian 10

Introduction

A hostname is a label used to identify your system on a network. You can change your hostname in Debian 10 (Buster) by using the hostname command or editing system files.

In this tutorial, we will cover different methods you can use to change the hostname in Debian 10.

Prerequisites

• A system running Debian 10 (Buster)
• An account with sudo level privileges
• Access to the terminal window/command line

Check the Current Hostname

Use the following command to check the current hostname:

hostname

The output displays the current hostname as plain text:

Change the Hostname

The first method involves using the hostname command to change the system name. The hostname command is used to obtain and change the system’s hostname.

It is important to note that any changes made using the hostname command are temporary. Unless you use the permanent method of changing the hostname outlined below, it will revert back to its original value after the next system reboot.

Follow the steps below to change the hostname:

1. Changing the hostname requires a user with sudo/root permissions. To switch to the root user, enter:

sudo -s

2. Use the hostname command to set up a new hostname:

hostname [name]

Where:

• [name]: The new hostname you want to set up.

In this example, we are using phoenixNAP as the new hostname:

hostname phoenixNAP

3. Check if the new hostname is set up correctly:

hostname

Change the Hostname Permanently

There are two ways to permanently change your hostname in Debian 10:

• Using the hostnamectl command;
• Editing the hostname file.

Regardless of the method you use, you also need to edit the system’s hosts file to match the changes in hostname.

To change the hostname permanently:

1. As the root user, open the hostname file:

sudo nano /etc/hostname

The first line of the hostname file lists the current hostname. Replace it with the new name you want to set up:

Press Ctrl+X to exit the file, then type Y and press Enter to save the changes.

Another method of setting a new permanent hostname is by using the hostnamectl command:

hostnamectl set-hostname [name]

2. Open the hosts file:

sudo nano /etc/hosts

3. In the hosts file, find all the instances of the old hostname and replace them with the new one:

Press Ctrl+X, and then type Y and press Enter to exit the file and save the changes you made.

4. Restart the hostname.sh shell script for the changes to take effect:

invoke-rc.d hostname.sh start

Hostname Format Restrictions

By default, static hostnames follow the same restrictions as Internet domain names:

• They have a minimum length of 2 and maximum length of 63 characters.
• They support letters from a to z, numbers from 0 to 9, and hyphens (–).
• They can’t start or end with a hyphen, or have two or more consecutive hyphens.

Using the hostname command with a special character produces the following error:

Pretty hostnames are high-level hostnames assigned to users or admins. These hostnames can contain special characters and are assigned using the hostnamectl command with the --pretty option:

hostnamectl set-hostname "[name]" --pretty

For example, if we want to set phoenixNAP’s test system as the pretty hostname:

hostnamectl set-hostname "phoenixNAP's test system" --pretty

Verify the Hostname Change

Verify the new hostname by running the following command:

hostnamectl

The output lists the new hostname in the Static hostname section:

Conclusion

After reading this tutorial, you should be able to change the hostname in Debian 10 using commands or editing system files.