DNSdomain

DNSdomain is not a formal term in DNS standards, but in general usage it refers to a domain within the Domain Name System. It denotes a portion of the DNS namespace under a domain name such as example.com, including all hosts and subdomains delegated to the same administrative authority. In practice, a DNSdomain is realized by a zone, a contiguous block of the DNS namespace whose data is stored in a zone file and served by one or more authoritative name servers.

A DNSdomain contains various resource records that map names to information needed by clients and services. Common records include A and AAAA for host IP addresses, CNAME for aliases, MX for mail servers, NS for delegation, and TXT for arbitrary text data. Each zone also contains an SOA (start of authority) record with administrative details and a serial number for version control. Zones can be subdivided into subdomains, each potentially managed by separate authorities with their own zone files.

Resolution and delegation involve a hierarchical process. A recursive resolver begins by querying root servers, then TLD servers, and finally the domain’s authoritative servers to obtain answers. Responses are cached to speed up repeated queries. Administrators can delegate subdomains by adding NS records and creating separate zone files, enabling distributed management across multiple teams or organizations.

Management and security vary by deployment. Domains are typically registered through registrars, with zone files hosted on authoritative servers. Security enhancements include DNSSEC, which provides cryptographic signing of records, and privacy or transport protections such as DNS over TLS (DoT) and DNS over HTTPS (DoH). Governance of the DNS involves IANA and ICANN oversight, with registries managing top-level domains and registrars selling domains to end users. DNSdomains are essential for web hosting, email routing, and many network services, using a consistent, hierarchical name space.