Fully Qualified Domain Name (FQDN) explained.

What is FQDN?

FQDN is the short acronym for Fully Qualified Domain Name. With it, you are able to see precisely the most full name of a specific domain name. And that refers not only to websites but also to servers. The Domain Name System (DNS) is created with a hierarchy order. It starts from the top, which is the root, then TLD, after that the domain, and the last is the specific hostname.

What does FQDN do?

Here is the full syntax of a fully qualified domain name (FQDN):

hostname. domain name. TLD 


Let’s view an example of a fully qualified domain name (FQDN):




Be aware that the dot “.” (root), which is last, is often neglected. Usually, the fully qualified domain names end with the TLD. However, there are cases in which you will need to add it. That depends on what software you are using.

The Fully Qualified Domain Name is suitable when you want to view where precisely an object exists in the Domain Name System hierarchy.


Here are the 3 elements of Fully Qualified Domain Name formatting. 

  • First is the TLD (Top Level Domain) – It is represented with the ending signs that we can see in an FQDN. Commonly 2 or 3 characters, such as .com, .edu, .net etc.
  • Subdomain – It is the domain that we can observe below the Top Level Domain. For example, Domain.com.
  • Hostname – It is represented with the symbols placed at the beginning of the FQDN. The most popular example is www in www.domain.com. A domain owner can generate many hostnames as they are associated with a subdomain. For example:
    • ftp.domain.com
    • mail.domain.com
    • www.domain.com

How to check the FQDN?

If you want to check if your device has an FQDN or its hostname is an easy task. It doesn’t matter if you are using a Windows 10, Linux, or macOS device. 

On Windows 10

  1. From the start menu, open your “Control Panel.” 
  2. Inside the Control Panel, open the System. 
  3. Inside the System, view the “Device specifications” and search for the “Device name”. 
  4. Next is the FQDN. 

On Linux 

  1. First, open the Terminal application. 
  2. Simply write this command: “hostname -f.”
  3. Press Enter, and you will see the FQDN. 

On macOS:

  1. First, open the Terminal application.
  2. Write down the command: “hostname -f.” The option “-f” means full. 
  3. Press the Enter, and you will see the FQDN. 

Why do you need FQDN?

The FQDN represents a unique address on the Internet. It is vital to the experience online. Imagine it, like you don’t have an FQDN. It is like you don’t have a website for people to visit. 

You will need FQDN if you want to install SSL certificates. This is because most websites are expected to have such a feature. 

With FQDN, you can access domain services, for example like email and File Transfer Protocol (FTP). If you want to connect a domain name email to an email app on your device manually, you will need the FQDN. 

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