An authoritative name server is actually responsible for a specific DNS zone. DNS Zones are a hierarchical concept.
The root name servers we covered earlier are responsible for the root zone. Each TLD name server is responsible for the zone covering its TLD. What we referred to as authoritative name servers are responsible for some even finer grained zones underneath that.
Zones don’t overlap. For example, the administrative authority of the TLD name server for the.com TLD doesn’t encompass the google.com domain. Instead, it ends at the authoritative server responsible for google.com
Allow for easier control over multiple levels of a domain
As the number of resource records in a single domain increases, it gets harder to manage. Network administrators can ease this pain by splitting up their configurations into multiple zones.
By splitting up regions into zone, we can have la.largecompany.com pa.largecompany.com sh.largecompany.com as subdomains, each with their own DNS zone.
Simple configuration files that declare all resource records for a particular zone
A zone file has to contain an SOA or a Start of Authority resource record declaration.
Declares the zone and the name of the name server that is authoritative for it
Indicate other name servers that might also be responsible for this zone
Just like how sub domains can go many layers deep, zones can be configured to do this too. But just like with sub domains, it’s rare to see zones deeper than just a few levels.
These let DNS resolvers ask for an IP and get the FQDN associated with it returned
Resolves an IP to a name