Editing Fully qualified domain name (section)

==Definition==
[[File:DNS schema.svg|The hierarchy of labels in a fully qualified domain name.|thumb|350px|alt=|right]] 
A fully qualified domain name is conventionally written as a list of domain labels separated using the [[full stop]] "{{code|.}}" character (''dot'' or ''period''). The top of the hierarchy in an FQDN begins with the rightmost label. For instance, in the FQDN {{code|somehost.example.com}}, {{code|com}} is a label directly under the [[DNS root zone|root zone]], {{code|example}} is nested under {{code|com}}, and finally {{code|somehost}} is nested under {{code|example.com}}.<ref name="rfc2181">{{Cite IETF |title=Clarifications to the DNS Specification |rfc=2181 |sectionname= |author1=R. Elz |author2=R. Bush |date=July 1997 |publisher=[[Internet Engineering Task Force|IETF]] |access-date=27 November 2024 }}</ref>

The topmost layer of every domain name is the [[DNS root zone]], which is expressed as an empty label and can be represented in an FQDN with a trailing dot, such as {{code|somehost.example.com.}}. A trailing dot is generally implied and often omitted by most applications. Trailing dots are required by the standard format for DNS [[zone file]]s, as well as to disambiguate cases where an FQDN does not contain any other label separators, such as the FQDNs for the root zone itself and any [[top-level domain]].<ref>{{cite web|last=Fisher|first=Tim|title=FQDN|url=http://pcsupport.about.com/od/termsf/g/fqdn-fully-qualified-domain-name.htm|publisher=About.com|access-date=20 March 2013|archive-date=3 April 2013|archive-url=https://web.archive.org/web/20130403142819/http://pcsupport.about.com/od/termsf/g/fqdn-fully-qualified-domain-name.htm|url-status=dead}}</ref>

The length of each label must be between 1 and 63 [[Octet (computing)|octets]], and the full domain name is limited to 255 octets, full stops included.<ref name="rfc2181" />