What is fqdn name
Last updated: April 1, 2026
Key Facts
- FQDN is the absolute path of a domain name with all subdomains explicitly stated
- An FQDN always includes a top-level domain (TLD) like .com, .org, or .edu
- FQDNs are used for email servers, web servers, and other internet resources
- Unlike relative domain names, an FQDN works the same regardless of context or location
- FQDNs are essential for DNS resolution to locate servers and services on the internet
What is an FQDN?
A Fully Qualified Domain Name (FQDN) is the complete hostname that uniquely identifies a computer or service on the internet. Unlike a partial domain name, an FQDN specifies every level of the domain hierarchy, starting from the host name and ending with the top-level domain. This makes it unambiguous—any device anywhere on the internet can find the resource using the FQDN.
FQDN Structure
An FQDN consists of multiple parts separated by dots, reading from left to right in order of increasing generality. The leftmost part is the hostname (like "mail" or "www"), followed by subdomain levels (if any), then the domain name, and finally the top-level domain (TLD). For example, in the FQDN "mail.google.com," "mail" is the hostname, "google" is the domain, and "com" is the TLD.
FQDN vs Partial Domain Names
- FQDN: Complete address that works everywhere (example.com.)
- Partial Name: May only work in specific network contexts (example)
- Relative Name: Context-dependent and ambiguous outside certain networks
- IP Address: Numerical address that maps to an FQDN through DNS
Common FQDN Examples
FQDNs are used extensively across the internet for various services and resources. Email servers use FQDNs like smtp.gmail.com to route messages. Web applications use FQDNs like docs.google.com to deliver specific services. Cloud providers use FQDNs to identify virtual machines and containers within their infrastructure.
FQDN and DNS Resolution
The Domain Name System (DNS) translates FQDNs into IP addresses so computers can find each other on networks. When you enter an FQDN into your browser, your computer queries DNS servers to discover the IP address associated with that name, then connects to that IP address.
Related Questions
What is the difference between FQDN and domain name?
A domain name is a general reference to a website or service, while an FQDN is the complete, absolute address including all subdomains and the top-level domain. For example, 'google.com' is a domain name, while 'mail.google.com' is an FQDN.
How is an FQDN used in email?
FQDNs identify mail servers and are used in email addresses as the domain part. The FQDN ensures your email is routed to the correct mail server globally, regardless of your local network configuration.
Can an FQDN have more than three parts?
Yes, an FQDN can have many parts. For example, 'api.staging.europe.example.com' is a valid FQDN with five parts total, allowing for complex organizational hierarchies.