DNS is a distributed, replicated, data query service mainly used on the
Internet for translating host names to
IP addresses. The three main components of DNS are: the domain name space and resource records, which are specifications for a
Tree structured name space and data associated with the names; name servers, which are server programs which hold information about the domain
Tree's structure and set information; and resolvers, being programs that extract information from name servers in response to client requests.