Introduction to the Domain Name System (DNS)

Domain name system (DNS) is a foundational element of internet protocol (IP) communications. The global DNS is effectively a distributed hierarchical database. Each "dot" in a domain name indicates a boundary between tiers in the hierarchy, with each name in between dots denoted as a label. To illustrate how domain information is organized and how a DNS server leverages this hierarchical data structure, this chapter gives an example name resolution. It includes a discussion regarding the distinction between zones and domains. DNS does require some basic client configuration prior to use. This initial configuration may be performed manually or by obtaining this information from a DHCP server. The chapter provides a brief overview of device resolver configuration. This background serves as a foundation for understanding the structure of "data at rest" on DNS servers and resolvers, as well as the process for locating DNS information within the global DNS tree.