Reference

DNS Dictionary

Plain-language definitions for common DNS terminology. Use the DNS Record Builder to generate records using these terms.

Jump to Resource Record Owner Label TTL Class Type Rdata Domain Node Domain Name
Resource Record (RR)
Structured data associated with a name or node in the DNS tree.
Format: owner ttl class type rdata
Example: www.example.com. 3600 IN A 192.0.2.127
Owner / name
A node in the domain name tree. For a specific RR, owner is the domain name where the RR is found. (RFC 1034 §3.6)
Consists of a sequence of labels.
Format: node.zone.tld. — the rightmost label is null (the root); the second-from-right is the TLD; the third-from-right is typically the organizational domain.
Label
A character string between the dots in a domain name.
Example: in www.example.com. the labels are www, example, and com.
TTL time to live
How long, in seconds, resolvers are permitted to cache this DNS resource record.
Class
Identifies the protocol family of the record. The internet class IN is used for virtually all modern DNS records.
Other values: CH (Chaosnet), HS (Hesiod).
Type
Specifies the kind of rdata that follows in the record.
Examples: A, AAAA, MX, SOA, NS, CNAME, PTR, TXT.
Rdata resource data
The payload of the resource record. Contents vary widely by record type.
A records carry an IPv4 address; AAAA records carry an IPv6 address; MX records carry a mail exchange hostname; CNAME records carry a canonical name target.
Domain
An administrative boundary within the domain name tree.
Subdomain
A domain contained within another domain.
Example: c.b.a. is a subdomain of b.a.
Node
A leaf or interior point in the domain name tree. (RFC 1034 §3.1)
Domain Name
The list of labels from a node up to the root of the tree. A domain name uniquely identifies a node. (RFC 1035 §3.6)