What is a DNS zone; how does it relate to a domain and a DNS record?

Short answer

A DNS zone is the part of the namespace for which a DNS server answers authoritatively (RFC 9499); e.g. the example.com zone contains the records of this name and of the names under it, such as www.example.com and mail.example.com. The domain is the name at the top of the zone; DNS records, on the other hand, are the individual rows within the zone (A, CNAME, MX…). In TR7 GTM, a zone is defined as a domain on the Domains tab under the DNS service; each domain independently carries its own Records list, its Default Mode value (Standalone, Disaster recovery or Datacenter) and its DNSSEC, SOA Format and Slave Server IPs settings.

Where It Is Used in TR7

Where	Field / label	What for
GTM → GTM Services → service name → Domains → Add	Domain Name	Defining the zone; the trailing dot is added automatically, and a name containing * is not accepted
Same form	Default Mode	The operating mode of all records in the zone
Same form	DNSSEC, SOA Format, Slave Server IPs	Per-zone signing, serial and zone transfer settings
GTM → GTM Services → service name → Records	Domain selection in the toolbar, Record Name, Record Type	Listing and adding the records within the zone
GTM → GTM Services → service name → Domains → domain preview	Dashboard	Monitoring only the queries that come to that zone

Layers

Concept	Example	In TR7 GTM
DNS service	The Frontend IP and port listened on (default 53)	Service Management
Zone (domain)	example.com.	Domains
Record	www → A → 203.0.113.10	Records

• A DNS service hosts multiple domains; each domain is bound to only one DNS service.
• When each domain is created, the SOA record of the zone is added automatically (What is an SOA record; what do its fields mean?).
• When a domain is deleted, all records of the zone, including the SOA record, are deleted together.

Common Misconceptions

• "Every subdomain is a separate zone." www.example.com is usually a record of the example.com zone; a subdomain is served as a separate zone only when delegation is done. In TR7, a subdomain such as api.example.com can also be added as a separate domain.
• "The domains in a service have to work in the same mode." Each domain carries its own Default mode value; Standalone, Disaster recovery and Datacenter domains can coexist in the same DNS service.
• "Adding the domain to GTM brings the queries to TR7." For the queries to come to TR7, the NS records in the parent zone must point to TR7 (What is an NS record?).

How it is done in the documentation

• Domains · What Is Domains?
• Domains · Operating Modes
• Domains · Domain Name Add Form
• GTM · Terminology

Related questions

• What is DNS; where is it used in TR7?
• What is an SOA record; what do its fields mean?
• What is an NS record?