FQDNs
FQDN stands for Fully Qualified Domain Name. It is a domain name that precisely specifies a host’s location in the hierarchical Domain Name System (DNS) and ends with the root label. In practice, many systems display FQDNs without the terminating dot, but the trailing dot denotes the root in DNS notation.
An FQDN is composed of a sequence of labels separated by dots. The rightmost label is the
DNS resolution uses the hierarchical structure: root servers delegate to TLD servers, which delegate to authoritative
Practical use: FQDNs identify servers in TLS certificates (CN or SAN fields), in configuration files, and in