Change Your Linux Server Hostname

Introduction

Changing your server’s hostname is a simple process, though it’s usually reserved for major events like branding updates. While not publicly visible, the hostname is critical because it appears in email headers and DNS records. This guide shows you how to update your hostname directly from the Linux command line using the hostnamectl command and editing key system files. We’ll also cover how to finalize the change in your Liquid Web account.

Prerequisites

Before you start make sure your system meets the following requirements:

• Operating system: RHEL/CentOS 7+, AlmaLinux 8+, Ubuntu 16.04+, Debian 9+, etc.
• Root SSH access 
• Fully Qualified Domain Name that is reachable via DNS.

Format: hostname.domainname.tld

Example: server.yourcompany.com

Why is an FQDN mandatory?

• DNS Resolution: For any external service (like email or remote connections) to reliably find your server, the FQDN must be translated into your server’s IP address. This critical function is handled by DNS (Domain Name System).
• Email Deliverability: Many spam filters perform reverse DNS lookups (checking if the IP matches the FQDN). Using an FQDN that resolves correctly is vital for preventing your emails from being marked as spam.
• SSL/TLS Certificates: Certificates used for securing web and control panel access (e.g., WHM/cPanel) must be issued to a valid FQDN.
• Best Practice: Choose a descriptive, simple hostname (e.g., host, server, vps) and combine it with a domain you own. Remember that once you set the FQDN on the server, you must update the corresponding DNS A Record (mapping the FQDN to the server’s IP address)

Step-by-step instructions

1. Choose a unique name for the server. Common choices include server1, host, or a name related to its function.
2. Identify the domain name you will use, such as yourdomain.com.
3. Combine them into the hostname.domain.com format.
4. To change your hostname, run either of the commands listed below. Be sure to replace the placeholder <your-new-hostname> with your actual hostname:
   hostnamectl set-hostname <your-new-hostname>
   or
   hostname <your-new-hostname> 
5. Log into your my.liquidweb.com to report your new hostname.
6. Click on Servers > My Servers section located on the left panel and find your server in the list.
7. Click on the “3 dots” menu located on the right side and click on Edit Hostname.
8. Provide your new hostname in the Server Hostname input field, and click Update save the changes made