RFC 1886 IPv6 DNS Extensions December 1995 1. INTRODUCTION Current support for the storage of Internet addresses in the Domain Name System (DNS)[1,2] cannot easily be extended to support IPv6 addresses[3] since applications assume that address queries return 32-bit IPv4 addresses only. To support the storage of IPv6 addresses we define the following extensions: o A new resource record type is defined to map a domain name to an IPv6 address. o A new domain is defined to support lookups based on address. o Existing queries that perform additional section processing to locate IPv4 addresses are redefined to perform additional section processing on both IPv4 and IPv6 addresses. The changes are designed to be compatible with existing software. The existing support for IPv4 addresses is retained. Transition issues related to the co-existence of both IPv4 and IPv6 addresses in DNS are discussed in [4]. 2. NEW RESOURCE RECORD DEFINITION AND DOMAIN A new 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 new record specific to the Internet class that stores a single IPv6 address. The 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). Thompson & Huitema Standards Track