This topic explains what Domain Name System (DNS) is and how it works. It also shows the different types of zones that can be defined on a DNS server.
Domain Name System (DNS) is a distributed database system for managing host names and their associated Internet Protocol (IP) addresses. Using DNS means that people can use simple names, such as www.jkltoys.com, to locate a host, rather than using the IP address (xxx.xxx.xxx.xxx). A single server might only be responsible for knowing the host names and IP addresses for a small subset of a zone, but DNS servers can work together to map all domain names to their IP addresses. DNS servers working together is what allows computers to communicate across the Internet.
DNS data is broken up into a hierarchy of domains. Servers are responsible to know only a small portion of data, such as a single subdomain. The portion of a domain for which the server is directly responsible is called a zone. A DNS server that has complete host information and data for a zone is authoritative for the zone. An authoritative server can answer queries about hosts in its zone, using its own resource records. The query process depends on a number of factors. Understanding DNS queries explains the paths a client can use to resolve a query.