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(The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document date (January 28, 2017) is 2645 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- ** Obsolete normative reference: RFC 6145 (Obsoleted by RFC 7915) Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group C. Bao 3 Internet-Draft X. Li 4 Intended status: Informational CERNET Center/Tsinghua 5 Expires: August 1, 2017 University 6 January 28, 2017 8 DNS46 for the IPv4/IPv6 Stateless Translator 9 draft-xli-behave-dns46-for-stateless-06 11 Abstract 13 The stateless translator can support IPv6-initiated communications as 14 well as IPv4-initiated communications for IPv6 hosts using IPv4- 15 translatable addresses. DNS support for the IPv6-initiated 16 communication is defined in the DNS64 specification. This document 17 defines the DNS46 function for the stateless translator. 19 Status of this Memo 21 This Internet-Draft is submitted to IETF in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at http://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on August 1, 2017. 36 Copyright Notice 38 Copyright (c) 2017 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (http://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3 55 3. DNS46 for the IPv4/IPv6 Stateless Translator . . . . . . . . . 3 56 3.1. Authoritative DNS server . . . . . . . . . . . . . . . . . 3 57 3.1.1. Static AAAA record . . . . . . . . . . . . . . . . . . 3 58 3.1.2. Varying AAAA record . . . . . . . . . . . . . . . . . . 4 59 3.2. DNS resolver . . . . . . . . . . . . . . . . . . . . . . . 4 60 3.2.1. DNS resolver for scenario 6 . . . . . . . . . . . . . . 4 61 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 62 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 63 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 64 7. Normative References . . . . . . . . . . . . . . . . . . . . . 5 65 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 67 1. Introduction 69 DNS mechanism is one of the functions model for the IPv4/IPv6 70 transition [RFC6144]. DNS64 allows IPv6 hosts to resolve names of 71 IPv4 hosts whereas DNS46 allows IPv4 hosts to resolve names of IPv6 72 hosts. 74 General DNS46 is considered harmful, as NAT-PT was deprecated by IETF 75 [RFC4966]. However, stateless translators can support IPv6-initiated 76 communications (scenario 1 and 3) which requires the DNS64 support 77 [RFC6146] [RFC6145], as well as IPv4-initiated communications 78 (scenario 2 and 4) which requires the DNS46 support [RFC6145]. 80 DNS64 is used for both stateful and stateless translators and it is 81 defined in [RFC6147]. DNS46 is only used for the stateless 82 translators and it is defines in this document. 84 2. Notational Conventions 86 The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, 87 SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this 88 document, are to be interpreted as described in [RFC2119]. 90 3. DNS46 for the IPv4/IPv6 Stateless Translator 92 The DNS46 for stateless IPv4/IPv6 translation is for the following 93 scenarios: 95 o Scenario 2: The IPv4 Internet to an IPv6 network. 97 o Scenario 6: An IPv4 network to an IPv6 network. 99 3.1. Authoritative DNS server 101 Since the destination is "an IPv6 network", DNS46 can be deployed as 102 an authoritative DNS server [RFC1035] in an IPv6 network. 104 3.1.1. Static AAAA record 106 This is very similar to the authoritative DNS configuration of dual- 107 stack hosts. The only difference is that in the dual-stack case, the 108 A record and AAAA record are independent, while in stateless 109 translation case, the hosts are typically IPv6 single stack (or for 110 some reason incapable of using IPv4 on a particular network) using 111 IPv4-translatable addresses and the A record MUST be derived from the 112 AAAA record based on the algorithm and the PREFIX information 114 [RFC6052]. 116 3.1.2. Varying AAAA record 118 If an IPv6 host has a varying AAAA record (that is, it could change 119 due to the IPv6-only host changing its IPv6 address and registering 120 its new address via, for example, DNS Dynamic Updates [RFC2316]), 121 then the dynamic DNS46 function is required. However, it is still 122 the authoritative DNS. When the authoritative DNS receives a dynamic 123 update containing AAAA record, it MUST synthesize corresponding A 124 record before signing the zone, which can be derived based on the 125 algorithm and the PREFIX information [RFC6052]. 127 3.2. DNS resolver 129 For scenario 2 (the IPv4 Internet to an IPv6 network) the 130 implementation of DNS46 resolver is almost impossible, since the IPv4 131 hosts are in the IPv4 Internet. 133 3.2.1. DNS resolver for scenario 6 135 However, for scenario 6 (an IPv4 network to IPv6 network) [RFC6144], 136 it is possible to use DNS resolver in an IPv4 network to synthesize A 137 records from the AAAA records based on the algorithm and the PREFIX 138 information [RFC6052]. 140 4. Security Considerations 142 When DNS46 function is provided by authoritative DNS server, DNS46 143 can support DNSSEC without problem. 145 When DNS46 function is provided by authoritative DNS server, the 146 reverse DNS is also under the same network operator's control which 147 may provide additional validation function for the IPv4-translatable 148 IPv6 addresses. 150 5. IANA Considerations 152 This memo adds no new IANA considerations. 154 Note to RFC Editor: This section will have served its purpose if it 155 correctly tells IANA that no new assignments or registries are 156 required, or if those assignments or registries are created during 157 the RFC publication process. From the author's perspective, it may 158 therefore be removed upon publication as an RFC at the RFC Editor's 159 discretion. 161 6. Acknowledgments 163 The authors would like to acknowledge the following contributors of 164 this document: Branimir Rajtar, Dan Wing and Kevin Yin. 166 7. Normative References 168 [RFC1035] Mockapetris, P., "Domain names - implementation and 169 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 170 November 1987, . 172 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 173 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ 174 RFC2119, March 1997, 175 . 177 [RFC2316] Bellovin, S., "Report of the IAB Security Architecture 178 Workshop", RFC 2316, DOI 10.17487/RFC2316, April 1998, 179 . 181 [RFC4966] Aoun, C. and E. Davies, "Reasons to Move the Network 182 Address Translator - Protocol Translator (NAT-PT) to 183 Historic Status", RFC 4966, DOI 10.17487/RFC4966, 184 July 2007, . 186 [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. 187 Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, 188 DOI 10.17487/RFC6052, October 2010, 189 . 191 [RFC6144] Baker, F., Li, X., Bao, C., and K. Yin, "Framework for 192 IPv4/IPv6 Translation", RFC 6144, DOI 10.17487/RFC6144, 193 April 2011, . 195 [RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation 196 Algorithm", RFC 6145, DOI 10.17487/RFC6145, April 2011, 197 . 199 [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful 200 NAT64: Network Address and Protocol Translation from IPv6 201 Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146, 202 April 2011, . 204 [RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van 205 Beijnum, "DNS64: DNS Extensions for Network Address 206 Translation from IPv6 Clients to IPv4 Servers", RFC 6147, 207 DOI 10.17487/RFC6147, April 2011, 208 . 210 Authors' Addresses 212 Congxiao Bao 213 CERNET Center/Tsinghua University 214 Room 225, Main Building, Tsinghua University 215 Beijing 100084 216 CN 218 Phone: +86 10-62785983 219 Email: congxiao@cernet.edu.cn 221 Xing Li 222 CERNET Center/Tsinghua University 223 Room 225, Main Building, Tsinghua University 224 Beijing 100084 225 CN 227 Phone: +86 10-62785983 228 Email: xing@cernet.edu.cn