DNS server which is responsible for hosts name in its zone, must keep data about hosts in database and provide it by request from remote computers. DNS database is textual file, which consists of RR records. These records describe computers and their functions in local zone. To conduct data exchange with remote servers, the DNS server software (it’s usually a ‘named’ program) must be launched.
First of all, there must be defined a zone in DNS server database, which this server is responsible for. Next, all host computers must be defined in it. And last, specific data can be defined (for example, about email and DNS servers). The record format war created in such a way that permits DNS server to get any data needed for its work.