What is FQDN?

FQDN stands for Fully Qualified Domain Name. It’s complete domain name for a computer or host on the internet. FQDN is made of two things: hostname and domain name.

Let me give you an example for demonstration.

FQDN for my mail server is myemailserver.abdullah.today.

The hostname is myemailserver. The domain is abdullah.today.


You will need:

  • IP Address
  • Hostname
  • FQDN

Edit hosts file

Edit the /etc/hosts file and append this like this.

# vim /etc/hosts
... myemailserver.abdullah.today myemailserver

Replace IP address with your host IP, hostname with what your want to set or what you already have set.

Edit hostname

Edit /etc/hostname and replace with your new hostname if you want to change hostname as well.

# vim /etc/hostname



Or you can use hostnamectl to set hostname.