How to Change Hostname on Linux: Ubuntu, Debian, CentOS

VDS / VPS Servers · 19.04.2026

The hostname is the server's network name. A correct hostname should be a fully qualified domain name (FQDN): server.example.com.

Change Hostname (systemd)

sudo hostnamectl set-hostname server.example.com
hostname --fqdn

Update /etc/hosts

sudo nano /etc/hosts
# Add:
127.0.1.1    server.example.com    server
YOUR.PUBLIC.IP    server.example.com    server

Verify the Change

hostname
hostname --fqdn
hostnamectl status

💡 Mail server: The VPS hostname must match the PTR record and Postfix HELO name. Format: mail.yourdomain.com.

⚠️ Never use bare localhost: A hostname of localhost or an unqualified name causes problems with Postfix, SSL generation, and control panels. Always use FQDN.