What is a DNS Zone?

About

A dns zone:

• is a namespace for a domain name (in the name hierarchical tree)
• is composed of all labels of a domain name except the last one on the left.

Example

• in foo.bar.com, the zone is bar.com
• in your.foo.bar.com, the zone is foo.bar.com

Usage

A zone defines:

• the administrator:
• the organization
• the authoritative nameservers (ie the servers that are the truth for your DNS record). In your apex domain, the records may be stored in more than one nameserver.

Apex Zone

Most of the time, you will have only one zone, the zone of your apex domain (the domain that you register).

If your nameservers are the nameservers of:

• Cloudflare, your apex zone is on the Cloudflare website/server
• Ovh, your apex zone is on the OVH website/server

Relationship

• A DNS zone can contain multiple subdomains
• Multiple zones can exist on the same server.

Zone file

Zones file are configuration files of the DNS nameservers that defines a zone.

They describe the namespace of that zone (the mail servers, …)