A zone is just a portion of a domain. The information about the zone is stored in the Domain Name Servers of the domain, which is authoritative for the zone. A single Name Server can be authoritative about many zones. For example, a domain inscription.com may contain all of the data for inscription.com, sales.inscription.com and accounts.inscription.com. But the zone inscription.com contains information only for inscription.com and references to the authoritative name servers for the subdomains.
The authoritative means that the server can provide any piece of information asked by the client about that domain. For example, consider you have two domains called Sales.inscription.com and Accounts.inscription.com on a machines called Server1.Sales.inscription.com and Server2.Accounts.inscription.com.
If a client asks Sales.inscription.com whether there is a machine called SalesServer1.inscription.com, then Sales.inscription.com can authoritatively say, yes or no because it is the authoritative name server for that domain. However, if the same question is asked by the Server2.Accounts.inscription.com then Server2.Accounts.inscription.com asks Sales.inscription.com whether such a machine exists or not. This is because Sales.inscription.com is the authoritative name server for the domain Sales.inscription.com.
When you install the DNS server, it creates, following two zones:
- Forward lookup zone: This zone allows you to perform name-to-address resolution (forward lookup queries). It simply resolves host names to IP addresses. At least one forward lookup zone must be configured on the name servers for the DNS Service to work. The forward lookup zone can be created by right-clicking the Forward Lookup Zone folder in the DNS Manager console and selecting Create a New Zone.
- Reverse lookup zone: This zone allows you to perform address-to-name resolution. It allows a DNS server to discover the DNS name of the host. It is the exact opposite of a forward lookup zone. Although this zone is not required, it provides your server to have full DNS functionality. It is also required to run troubleshooting tools such as NSLOOKUP. The reverse lookup zone can be created by right-clicking the Reverse Lookup Zone folder in the DNS Manager console and selecting the Create a New Zone.