Resource Records (RRs)

Entity of DNS DB (record)

<name> <ttl> <class> <type> <data>
name: a domain name = lookup key
ttl: lifetime of cached RRs in seconds
(don't confuse it with TTL field of IP Header)
class: typically IN (Internet Domain)
type: type of record (A, NS, MX, PTR, SOA...)
data: data depending on class/type
e.g. an IPv4 address for A RR
can consist of multiple fields