FQDN

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Fully qualified domain name.

A fully qualified domain name (FQDN), sometimes also referred as absolute domain name, is a domain name that specifies its exact location in the tree hierarchy of the Domain Name System (DNS). It specifies all domain levels, including the top-level domain and the root domain. A fully qualified domain name is distinguished by its unambiguity; it can only be interpreted one way.

For example, given a device with a local hostname myhost and a parent domain name example.com, the fully qualified domain name is myhost.example.com. The FQDN therefore uniquely identifies the device – while there may be many hosts in the world called myhost, there can only be one myhost.example.com. In the Domain Name System, and most notably, in DNS zone files, a fully qualified domain name is specified with a trailing dot – for example,
somehost.example.com.