In the Domain Name System, hostnames are mapped to IPv6 addresses by AAAA resource records, so-called quad-A records. For reverse lookup the IETF reserved the domain ip6.arpa, where the name space is hierarchically divided by the 1-digit hexadecimal representation of nibble units (4 bits) of the IPv6 address.
As in IPv4, each host is represented in the DNS by two DNS records: an address record and a reverse mapping pointer record. For example, a host computer named derrick in zone example.com has the Unique Local Address fdda:5cc1:23:4::1f. Its quad-A address record is
derrick.example.com. IN AAAA fdda:5cc1:23:4::1f
and its IPv6 pointer record is
f.220.127.116.11.0.0.0.0.0.0.0.0.0.0.0.4.0.0.0.3.18.104.22.168.c.c.5.a.d.d.f.ip6.arpa. IN PTR derrick.example.com.
This pointer record may be defined in a number of zones, depending on the chain of delegation of authority in the zone d.f.ip6.arpa.
The DNS protocol is independent of its Transport Layer protocol. Queries and replies may be transmitted over IPv6 or IPv4 transports regardless of the address family of the data requested.
|TTL||Time to live in seconds|
|RDLENGTH||Length of RDATA field|
|RDATA||128-bit IPv6 address, network byte order|