A fully qualified domain name (FQDN) is the complete domain name for a specific computer, or host, on the internet. The fully qualified domain name consists of a list of domain labels representing the hierarchy from the lowest relevant level in the DNS to the top-level domain (TLD). The domain labels are concatenated using the full stop (dot, period) character as separator between labels:
[hostname].[domain].[tld]
For example, a mail server for nettway.com is mail.nettway.com:
- The first part of the [mail] is the hostname, and the host is located within the domain, [nettway]
- the second part is the domain of [nettway]
- and the last part [com] is the TLD (known as the top-level domain, but also can be a country code top-level domain, ccTLD, e.g .com.au)