FQDN – Fully Qualified Domain Name | A Comprehensive Guide

Fully Qualified Domain Name – FQDN

A fully qualified domain name (FQDN) is a complete domain name having a hostname and domain name that can be assigned to an IP address. A fully qualified domain name will always specify the exact location of a computer or a host on the Internet.

Let’s have a deep conversation about the FQDN.

fully qualified domain name - fqdn
fully qualified domain name – FQDN

The FQDN is also known as an absolute domain name. It contains two parts: the hostname and the domain name. For example, our official website is www.redserverhost.com whereas the URL of our blog is blog.redserverhost.comBoth of them are FQDN like www.amazon.com or www.dps.edu.

In the above example, .edu or .com is a top-level domain (TLD) whereas ‘amazon’ or ‘redserverhost’ is a second-level domain. The top-level domain (TLD) is similar to the root directory on a standard workstation, where all the other directories and folders originated.

Likewise, the same applies to the homepage URL of websites. For example, www.redserverhost.com is an FQDN as it consists of a top-level domain name and second-level domain name along with the exact web address. In this example, www is the name is the hostname, .com is the top-level domain, and ‘redserverhost’ is the second-level domain.

Other than this, a fully qualified domain could also consist of a subdomain. The subdomain is located on the left side of the second-level domain. For example, blog.redserverhost.com is a part of the main domain which is redserverhost.comand the word ‘blog’ is a subdomain. It’s not necessary to have a subdomain on every website.

Partially Qualified Domain Name – PQDN

Partially qualified domain names are slightly different from the FQDNs as it only includes the hostname or domain name on a web address.

You can say “An incomplete FQDN is a partially qualified domain name (PQDN)“.

Generally, we mostly use PQDNs to search for something as they’re shorter, and help visitors to remember the website name easily. For example, whether you type redserverhost.com or www.redserverhost.comyou’ll land on the https://redserverhost.com – our homepage URL. Still, most of the visitors will prefer typing redserverhost.com instead of typing www.redserverhost.com or https://redserverhost.com.

Use of fully qualified domain name (FQDN)

FQDNs are usually used in any interaction on the Internet as they’re easy to remember compared to the IP Addresses. Below are some of the scenarios of when to use FQDNs.

  • FQDN in Secure Socket Layer (SSL)

A secure socket layer (SSL) protects data traveling between a web server and a browser by adding an extra layer of security. An SSL certificate is issued to an FQDN, so you may not be able to use SSL services properly without it.

  • FQDN in File Transfer Protocol (FTP)

To access an FTP account via any FTP client such as FileZilla, WinSCP, Cyberduck, etc. You’ll have to specify the FQDN with the format of [hostname] [subdomain] [TLD]. If you want to access a specific domain service or protocol, you’ll have to specify the fully qualified domain name.

  • FQDN in server migration

If you want to migrate your server to a new server with a different IP address, you can use FQDN instead of IP address to quickly change your DNS record. This will also reduce the outages you’ll face in the IP address change.

  • FQDN in connecting to a remote server

You can easily make a remote host by specifying the FQDN name in the domain name system (DNS). Usually, a hostname error occurs when connecting to a remote server by entering the IP address instead of FQDN, to avoid these kinds of errors, it’s recommended to use FQDN to connect to a server. Your application may not be able to resolve the hostname in the case of connecting to a remote server via IP address.


A fully qualified domain name (FQDN) enables a specific server or a computer on the internet to be uniquely identified within the domain name system (DNS).

  • Below I’m mentioning some of the qualities that a fully qualified domain name (FQDN) contains:
    • Hostname
    • Subdomain (If any)
    • Second-level domain
    • Top-level domain (TLD)
    • Trailing Period

Unlike fully qualified domain names, partially qualified domain names (PQDNs) are more effectively used by the users as they’re shorter than FQDNs, easy to remember, and also they don’t have any drawbacks when being used in the front-end cases. PQDN contains only the hostname or domain name – second-level domain and TLD.

FQDN is used when someone wants to connect to a remote server, migrate to a new server, purchase an SSL certificate, connect to a remote host, or a remote machine.

We hope now you got the clear-cut knowledge of FQDN. If you’re looking to purchase a domain name, we’ll recommend you to purchase it from Redserverhost as we’re one of the most reliable Domain & Web Hosting Providers.

Other than this, you can contact us on Facebook and Twitter for any further assistance or inquiries.

Scroll to Top