FQDN - What is FQDN ?

A FQDN is a Fully Qualified Domain Name.


A FQDN is a complete DNS name. For example, if a server named snoopy existed at the White House, the FQDN of that server might be snoopy.whitehouse.gov.

Technically, a FQDN must end in a period. This rule is almost always ignored.

A FQDN is limited to a maximum length of 255 characters.

In addition, the FQDN is also limited by the rules which limit each of its component sections. Each section must be made up only of letters, numbers, and the hyphen character. The characters are not case-sensitive. Each section of an FQDN can be up to 63 characters long.