@techreport{boucadair-dnsop-prefix64-02, number = {draft-boucadair-dnsop-prefix64-02}, type = {Internet-Draft}, institution = {Internet Engineering Task Force}, publisher = {Internet Engineering Task Force}, note = {Work in Progress}, url = {https://datatracker.ietf.org/doc/draft-boucadair-dnsop-prefix64/02/}, author = {Mohamed Boucadair}, title = {{An EDNS0 Option for Sharing Pref64::/n}}, pagetotal = 9, year = 2022, month = jan, day = 5, abstract = {This document specifies an Extension Mechanisms for DNS (EDNS0) option to convey the IPv6 prefix used to build IPv4-converted IPv6 addresses. When conveyed in a DNS query, the option communicates the IPv6 prefix used in the network from which the query was originated. Such a network is assumed to enable a Network Address and Protocol Translation from IPv6 clients to IPv4 servers (NAT64) function. DNS64-capable servers will use that prefix to build synthesized AAAA records, rather than relying on a preconfigured prefix. When conveyed in a DNS reply, the option conveys the IPv6 prefix that is used by a DNS64-capable server to synthesized AAAA records. Such information helps to automatically detect mismatches between the local NAT64 configuration and the one enforced at the DNS64 server. Also, security-aware and validating hosts may use the new EDNS0 option to signal the presence of a NAT64 function. That signal is used by the DNS server to fill the additional section of the AAAA reply in order to supply A RRs of the target. Dual queries and delays are thus avoided. This document updates RFC 6147.}, }