TCP/IP Guide

DNS Labels, Names, and Syntax Rules

We've seen how the DNS name space hierarchy allows us to arrange domains into a virtual tree that reflects the characteristics of how the devices themselves are organized. While using a hierarchical name space is inherently more complex than a flat name space, it yields a powerful result: the ability to specify names that can be locally managed while remaining globally unique. At the same time, the complexity of the tree yields the benefit of relatively simple name construction using domain identifiers.

DNS Labels and Label Syntax Rules

Naming in DNS begins with giving each domain, or node, in the DNS name space a text label. The label identifies the domain within the structure and must follow several syntax rules: ...