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DNS Zones

A zone is a contiguous portion of the domain namespace for which a DNS server has the authority to resolve DNS queries. The namespace can be divided up into zones, which store name information about one or more DNS domains or portions of a domain. A zone is the authoritative source for information about each domain name included in that zone. You can configure a single DNS server to host multiple zones, but conversely, you can also configure multiple servers to host one or more zones to provide fault tolerance and distribute name resolution and administrative workload.

Multiple zones in a domain name space can be used to distribute administrative tasks to different groups. However, a zone must encompass a contiguous domain name space. You cannot create a zone that consists of only of and because these two domains are not contiguous - the admin and finance subdomains are independent of each other and can only be combined into a single DNS zone if the domain is also included in the zone.

Zone files contain information that a DNS server references to resolve host names to IP addresses and to resolve IP addresses to host names. This information is stored as resource records that populate the zone file. A zone file contains the name resolution data for a zone, including resource records that contain information for answering DNS queries. Resource records are database entries that contain various attributes of a computer, such as the host name or FQDN, the IP address, or the alias. DNS servers can contain various types of resource records.

Next: Resource Records