TCP/IP Tutorial and Technical Overview - IBM Redbooks

The following extensions are specified:
► A new resource record type, AAAA, which maps the domain name to the IPv6
address
► A new domain, which is used to support address-to-domain name lookups
► A change to the definition of existing queries so that they will perform correct
processing on both A and AAAA record types
9.4.1 Format of IPv6 resource records
RFC 3596 defines the format of the AAAA record as similar to an A resource
record, but with the 128-bit IPv6 address encoded in the data section and a Type
value of 28 (decimal).
A special domain, IP6.INT, is defined for inverse (address-to-host name) lookups
(similar to the in-addr.arpa domain used in IPv4). As in IPv4, the address must
be entered in reverse order, but hexadecimal digits are used rather than decimal
notation.
For example, for the IPv6 address:
2222:0:1:2:3:4:5678:9ABC
The inverse domain name entry is:
c.b.a.9.8.7.6.5.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.2.2.2.2.IP6.INT.
So, if the previous address relates to the node ND1.test.com, we might expect to
see the following entries in the name server zone data:
$origin test.com.
ND1 99999 IN AAAA 2222:0:1:2:3:4:5678:9ABC
cba98765400030002000100000002222.IP6.INT. IN PTR ND1 2
Proposed changes to resource records
The IPv6 addressing system has been designed to allow for multiple addresses
on a single interface and to facilitate address renumbering (for example, when a
company changes one of its service providers). RFC 3596 – DNS Extensions to
Support IP Version 6 proposes changes to the format of the AAAA resource
record to simplify network renumbering.
2 All characters making up the reversed IPv6 address in this PTR entry should be separated by a
period(.). These have been omitted in this example for clarity.
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