2. New resource record definition and domain

A record type is defined to store a host's IPv6 address. A host that has more than one IPv6 address must have more than one such record.

2.1. AAAA record type

The AAAA resource record type is a record specific to the Internet class that stores a single IPv6 address.

The IANA assigned value of the type is 28 (decimal).

2.2. AAAA data format

A 128 bit IPv6 address is encoded in the data portion of an AAAA resource record in network byte order (high-order byte first).

2.3. AAAA query

An AAAA query for a specified domain name in the Internet class returns all associated AAAA resource records in the answer section of a response.

A type AAAA query does not trigger additional section processing.

2.4. Textual format of AAAA records

The textual representation of the data portion of the AAAA resource record used in a master database file is the textual representation of an IPv6 address as defined in [3].

2.5. IP6.ARPA Domain

A special domain is defined to look up a record given an IPv6 address. The intent of this domain is to provide a way of mapping an IPv6 address to a host name, although it may be used for other purposes as well. The domain is rooted at IP6.ARPA.

An IPv6 address is represented as a name in the IP6.ARPA domain by a sequence of nibbles separated by dots with the suffix ".IP6.ARPA". The sequence of nibbles is encoded in reverse order, i.e., the low-order nibble is encoded first, followed by the next low-order nibble and so on. Each nibble is represented by a hexadecimal digit. For example, the reverse lookup domain name corresponding to the address

4321:0:1:2:3:4:567:89ab

would be

b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.IP6.ARPA.