A fully qualified domain name (FQDN), sometimes also referred to as an absolute domain name or FQDN hostname, 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 zone.
A fully qualified domain name (FQDN) example: sub.domain.com
To put it in simpler words, a FQDN is a hostname with 2 “.” (dots), like a subdomain.
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