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What is a Fully Qualified Domain Name (FQDN)?
When working with domains and DNS management understanding what a FQDN is can be very helpful. This article will help explain the concept of a FQDN and a domains different components.
The Parts of a Domain
A domain is made up of a two essential parts, the Top-Level Domain (TLD) and the main Domain Name which is what you register. The other component of domain names are the subdomains.
- DNS Root: A DNS zone that contains all Top-Level Domains
- The DNS root is often designated by a ‘.’ following the TLD.
- Top-Level Domain or TLD
- Domain Name, or the domain you bought
, domains are actually interpreted by computers
from right-to-left rather than left-to-right. This is done with good reason, the same ‘Domain name’ could be registered with multiple TLDs. By reading right-to-left
this allows DNS resolution to be accurate and efficient. For example, when pulling up www.liquidweb.com
, instead of asking for all possible ‘liquidweb’
domains your browser specifically asks the main ‘.com’
nameserver for the ‘liquidweb’
So what exactly is a FQDN?
Now armed with knowledge of domain components understanding FQDN should be much easier.
A FQDN is simply a domain that includes all the necessary components to resolve an exact location. Often referred to as an absolute domain name.
So a FQDN is not simply liquidweb, nor is it just www; a FQDN is the complete domain name which resolves to the main, or ‘root’ domain. Generally this means that the domain will include the ‘root’, however this is not a requirement.
With that in mind the following are examples of FQDNs:
- www.google.com – or – www.google.com.
- liquidweb.com – or – liquidweb.com.
- bing.co.uk – or – bing.co.uk.