rfc-3596

DNS Extensions to Support IP Version 6

S. Thomson, C. Huitema, V. Ksinant, M. Souissi

date2003-10 streamIETF areaint wgdnsext statusINTERNET STANDARD pages8 canonicalhttps://www.rfc-editor.org/rfc/rfc3596 doi10.17487/RFC3596

This document defines the changes that need to be made to the Domain Name System (DNS) to support hosts running IP version 6 (IPv6). The changes include a resource record type to store an IPv6 address, a domain to support lookups based on an IPv6 address, and updated definitions of existing query types that return Internet addresses as part of additional section processing. The extensions are designed to be compatible with existing applications and, in particular, DNS implementations themselves. [STANDARDS-TRACK]

obsoletes

rfc-1886 — DNS Extensions to support IP version 6
rfc-3152 — Delegation of IP6.ARPA

also

std-88

Extracted elements (11)

design-rationale §1

The extensions are designed to be compatible with existing DNS software; existing support for IPv4 addresses is retained unchanged. The IP protocol version used for querying is independent of the protocol version of the resource records (IPv4 transport may query IPv6 records and vice versa).

dns, ip

interoperability-note §Appendix A

SRV query types were explicitly added to the list of query types requiring dual A/AAAA additional section processing in this document, correcting an omission from RFC 1886.

dns, ip

interoperability-note §Appendix A

This document obsoletes RFC 1886 and RFC 3152, replacing the IP6.INT reverse lookup domain with IP6.ARPA as mandated by RFC 3152. Implementations previously using IP6.INT must migrate to IP6.ARPA.

dns, ip

normative-requirement §3 MUST

All existing query types that perform type A additional section processing (NS, SRV, MX) must be redefined to perform both type A and type AAAA additional section processing. Name servers must add relevant IPv4 and IPv6 addresses to the additional section when processing these queries.

dns, ip

protocol-element §2.3

An AAAA query for a domain name in the Internet class returns all associated AAAA resource records in the answer section. A type AAAA query does not trigger additional section processing.

dns, ip

protocol-element §2.1

The AAAA resource record type (IANA type value 28) is defined for the Internet class to store a single IPv6 address. A host with more than one IPv6 address must have more than one AAAA record.

dns, ip

protocol-element §2.5

The IP6.ARPA domain supports reverse lookups from an IPv6 address to a host name. An IPv6 address is represented as a sequence of nibbles separated by dots in reverse order with the suffix ".IP6.ARPA".

dns, ip

protocol-element §2.4

The textual representation of AAAA record data in a master database file follows the IPv6 address text format defined in RFC 3513.

dns, ip

security-consideration §4

Any information obtained from the DNS must be regarded as unsafe unless DNSSEC (RFC 2535) or TSIG (RFC 2845) techniques are used. The AAAA record type and IP6.ARPA domain do not change the security model; this specification introduces no new security problems and solves none.

dns, security

wire-format §2.5

For IP6.ARPA reverse lookup names, each nibble of the IPv6 address is encoded as a hexadecimal digit, separated by dots, with the low-order nibble first (reversed), and the suffix ".IP6.ARPA." appended. For example, 4321:0:1:2:3:4:567:89ab maps to 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.

dns, ip

wire-format §2.2

The AAAA record data field encodes a 128-bit IPv6 address in network byte order (high-order byte first). The IANA-assigned type code is 28 (decimal).

dns, ip