idnits 2.17.1 draft-ietf-v6ops-ivi-icmp-address-04.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document seems to lack the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords. (The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document date (September 5, 2012) is 4251 days in the past. Is this intentional? Checking references for intended status: Best Current Practice ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** 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 X. Li 3 Internet-Draft C. Bao 4 Intended status: BCP CERNET Center/Tsinghua 5 Expires: March 9, 2013 University 6 D. Wing 7 R. Vaithianathan 8 Cisco 9 G. Huston 10 APNIC 11 September 5, 2012 13 Stateless Source Address Mapping for ICMPv6 Packets 14 draft-ietf-v6ops-ivi-icmp-address-04 16 Abstract 18 A stateless IPv4/IPv6 translator may receive ICMPv6 packets 19 containing non IPv4-translatable addresses as the source. These 20 packets should be passed across the translator as ICMP packets 21 directed to the IPv4 destination. This document presents 22 recommendations for source address translation in ICMPv6 headers to 23 handle such cases. 25 Status of this Memo 27 This Internet-Draft is submitted to IETF in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at http://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on March 9, 2013. 42 Copyright Notice 44 Copyright (c) 2012 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (http://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 60 2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3 61 3. Problem Statement and Considerations . . . . . . . . . . . . . 3 62 3.1. Considerations . . . . . . . . . . . . . . . . . . . . . . 3 63 3.2. Recommendations . . . . . . . . . . . . . . . . . . . . . . 4 64 4. ICMP Extension . . . . . . . . . . . . . . . . . . . . . . . . 4 65 5. Stateless Address Mapping Algorithm . . . . . . . . . . . . . . 4 66 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 67 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 68 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 69 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 70 9.1. Normative References . . . . . . . . . . . . . . . . . . . 5 71 9.2. Informative References . . . . . . . . . . . . . . . . . . 5 72 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 74 1. Introduction 76 [RFC6145] section 5.2 of the "IP/ICMP Translation Algorithm" 77 document. states that "the IPv6 addresses in the ICMPv6 header may 78 not be IPv4-translatable addresses and there will be no corresponding 79 IPv4 addresses representing this IPv6 address. In this case, the 80 translator can do stateful translation. A mechanism by which the 81 translator can instead do stateless translation is left for future 82 work." This document, Stateless Source Address Mapping for ICMPv6 83 Packets, provides recommendations for this case. 85 2. Notational Conventions 87 The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, 88 SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this 89 document, are to be interpreted as described in [RFC2119]. 91 3. Problem Statement and Considerations 93 When a stateless IPv4/IPv6 translator receives an ICMPv6 message 94 [RFC4443] (for example "Packet Too Big") sourced from an non-IPv4- 95 translatable IPv6 address, bound for to an IPv4-translatable IPv6 96 address, the translator needs to pick a source address with which to 97 generate an ICMP message. For the reasons discussed below, this 98 choice is problematic. 100 3.1. Considerations 102 The source address used, should not cause the ICMP packet to be a 103 candidate for discarding. The possibility of uRPF filters in the 104 path are a critical consideration [RFC3704] which precludes the use 105 of private IPv4 address space [RFC1918] in this context. 107 IPv4/IPv6 translation is intended for use in contexts where IPv4 108 addresses may not be readily available, so it is not considered 109 appropriate to assign IPv4-translatable IPv6 addresses for all 110 internal points in the IPv6 network that may originate ICMPv6 111 messages. 113 Another consideration for source selection is that it be possible for 114 the IPv4 recipients of the ICMP message to be able to distinguish 115 between different IPv6 network origination of ICMPv6 messages, (for 116 example, to support a traceroute diagnostic utility that provides 117 some limited network level visibility across the IPv4/IPv6 118 translator). This consideration implies that an IPv4/IPv6 translator 119 needs to have a pool of IPv4 addresses for mapping the source address 120 of ICMPv6 packets generated from different origins, or to include the 121 IPv6 source address information for mapping the source address by 122 others means. Currently, the TRACEROUTE and MTR [MTR] are the only 123 consumers of translated ICMPv6 messages that care about the ICMPv6 124 source address. 126 3.2. Recommendations 128 The recommended approach to source selection is to use the a single 129 (or small pool) of public IPv4 address as the source address of the 130 translated ICMP message and leverage ICMP extension [RFC5837] to 131 include IPv6 address as an Interface IP Address Sub-Object. 133 4. ICMP Extension 135 In the case of either a single public IPv4 address (the IPv4 136 interface address or loopback address of the translator) or a pool of 137 public IPv4 addresses, the translator SHOULD implement ICMP extension 138 defined by [RFC5837]. The ICMP message SHOULD include the Interface 139 IP Address Sub-Object, and specify the source IPv6 addresses of the 140 original ICMPv6. When an enhanced traceroute application is used, it 141 can derive the real IPv6 source addresses which generated the ICMPv6 142 messages. Therefore, it would be able improve on visibility towards 143 the origin rather than simply blackholing at or beyond the 144 translator. In the future, a new ICMP extension whose presence 145 indicates that the packet has been translated and that the source 146 address belongs to the translator, not the originating node can also 147 be considered. 149 5. Stateless Address Mapping Algorithm 151 If a pool of public IPv4 addresses is configured on the translator, 152 it is RECOMMENDED to randomly select the IPv4 source address from the 153 pool. This can superficially avoid the appearance of a routing loop 154 in tools unaware of the ICMP extension such as traceroute. An 155 enhanced traceroute application is RECOMMENDED in order to obtain the 156 IPv6 source addresses which generated the ICMPv6 messages. 158 6. Security Considerations 160 This document recommends the generation of IPv4 ICMP messages from 161 IPv6 ICMP messages. These messages would otherwise have been 162 discarded. It is not expected that new considerations result from 163 this change. As with a number of ICMP messages, a spoofed source 164 address may result in replies arriving at hosts that did not expect 165 them using the facility of the translator. 167 7. IANA Considerations 169 There is no consideration requested of IANA. 171 8. Acknowledgments 173 The authors would like to acknowledge the following contributors of 174 this document: Kevin Yin, Chris Metz, Neeraj Gupta and Joel Jaeggli. 175 The authors would also like to thank Ronald Bonica, Ray Hunter, 176 George Wes, Yu Guanghui, Sowmini Varadhan, David Farmer, Fred Baker, 177 Leo Vegoda, Joel Jaeggli, Henrik Levkowetz, Henrik Levkowetz, Randy 178 Bush and Warren Kumari for their comments and suggestions. 180 9. References 182 9.1. Normative References 184 [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and 185 E. Lear, "Address Allocation for Private Internets", 186 BCP 5, RFC 1918, February 1996. 188 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 189 Requirement Levels", BCP 14, RFC 2119, March 1997. 191 [RFC3704] Baker, F. and P. Savola, "Ingress Filtering for Multihomed 192 Networks", BCP 84, RFC 3704, March 2004. 194 [RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control 195 Message Protocol (ICMPv6) for the Internet Protocol 196 Version 6 (IPv6) Specification", RFC 4443, March 2006. 198 [RFC5837] Atlas, A., Bonica, R., Pignataro, C., Shen, N., and JR. 199 Rivers, "Extending ICMP for Interface and Next-Hop 200 Identification", RFC 5837, April 2010. 202 [RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation 203 Algorithm", RFC 6145, April 2011. 205 9.2. Informative References 207 [MTR] "http://www.bitwizard.nl/mtr/". 209 Authors' Addresses 211 Xing Li 212 CERNET Center/Tsinghua University 213 Room 225, Main Building, Tsinghua University 214 Beijing 100084 215 CN 217 Phone: +86 10-62785983 218 Email: xing@cernet.edu.cn 220 Congxiao Bao 221 CERNET Center/Tsinghua University 222 Room 225, Main Building, Tsinghua University 223 Beijing 100084 224 CN 226 Phone: +86 10-62785983 227 Email: congxiao@cernet.edu.cn 229 Dan Wing 230 Cisco Systems, Inc. 231 170 West Tasman Drive 232 San Jose, CA 95134 233 USA 235 Email: dwing@cisco.com 237 Ramji Vaithianathan 238 Cisco Systems, Inc. 239 A 5-2, BGL 12-4, SEZ Unit, 240 Cessna Business Park, Varthur Hobli 241 Sarjapur Outer Ring Road 242 BANGALORE KARNATAKA 560 103 243 INDIA 245 Phone: +91 80 4426 0895 246 Email: rvaithia@cisco.com 248 Geoff Huston 249 APNIC 251 Email: gih@apnic.net