--- 1/draft-ietf-6man-ra-pref64-03.txt 2019-08-11 21:13:14.527144824 -0700 +++ 2/draft-ietf-6man-ra-pref64-04.txt 2019-08-11 21:13:14.551145433 -0700 @@ -1,18 +1,18 @@ IPv6 Maintenance L. Colitti Internet-Draft J. Linkova Intended status: Standards Track Google -Expires: January 25, 2020 July 24, 2019 +Expires: February 12, 2020 August 11, 2019 Discovering PREF64 in Router Advertisements - draft-ietf-6man-ra-pref64-03 + draft-ietf-6man-ra-pref64-04 Abstract This document specifies a Router Advertisement option to communicate NAT64 prefixes to clients. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. @@ -20,21 +20,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on January 25, 2020. + This Internet-Draft will expire on February 12, 2020. Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -106,22 +106,22 @@ o IPv4 address literals on an IPv6-only host. As described in [RFC8305] section 7.1, IPv6-only hosts connecting to IPv4 address literals can resolve the IPv4 literal to an IPv6 address. o 464XLAT [RFC6877]. 464XLAT is widely deployed and requires that the host be aware of the NAT64 prefix. o Trusted DNS server. AAAA synthesis is required for the host to be able to use a DNS server not provided by the network (e.g., a DNS- - over-TLS server with which the host has an existing trust - relationship). + over-TLS server ([RFC7858]) with which the host has an existing + trust relationship). o Networks with no DNS64 server. Hosts that support AAAA synthesis and that are aware of the NAT64 prefix in use do not need the network to perform the DNS64 function at all. 3. Why include the NAT64 prefix in Router Advertisements Fate sharing: NAT64 requires a routing to be configured. IPv6 routing configuration requires receiving an IPv6 Router Advertisement [RFC4861]. Compared to currently-deployed NAT64 prefix discovery @@ -138,25 +138,25 @@ new Router Advertisement. Deployability: all IPv6 hosts and networks are required to support [RFC4861]. Other options such as [RFC7225] require implementing other protocols. 4. Semantics To support prefix lengths defined in ([RFC6052]) this option contains the prefix length field. However as /96 prefix is considered to be - the most common usecase, the prefix length field is optional and only - presents for non-/96 prefixes. It allows to keep the option length - to a minimum (16 bytes) for the most common case and increase it to - 20 bytes for non-/96 prefixes only (see Section 5 below for more - details). + the most common use case, the prefix length field is optional and + only presents for non-/96 prefixes. It allows to keep the option + length to a minimum (16 bytes) for the most common case and increase + it to 20 bytes for non-/96 prefixes only (see Section 5 below for + more details). This option specifies exactly one NAT64 prefix for all IPv4 destinations. If the network operator desires to route different parts of the IPv4 address space to different NAT64 devices, this can be accomplished by routing more specifics of the NAT64 prefix to those devices. For example, if the operator would like to route 10.0.0.0/8 through NAT64 device A and the rest of the IPv4 space through NAT64 device B, and the operator's NAT64 prefix is 2001:db8:a:b::/96, then the operator can route 2001:db8:a:b::a00:0/104 to NAT64 A and 2001:db8:a:b::/64 to NAT64 B. @@ -252,66 +252,66 @@ (e.g. by using PCP ([RFC7225]) and/or by resolving IPv4-only fully qualified domain name ([RFC7050]) in addition to receiving the Pref64 RA option); o The pref64 option presents in a single RA more than once; o the host receives multiple RAs with different Pref64 prefixes on one or multiple interfaces. When multiple Pref64 were discovered via RA Pref64 Option (the Option - presents more than once in a singe RA or multiple RAs were received), - host behaviour with regards to synthesizing IPv6 addresses from IPv4 - addresses SHOULD follow the recommendations given in Section 3 of - [RFC7050], limited to the NAT64 prefixes that have non-zero - lifetime.. + presents more than once in a single RA or multiple RAs were + received), host behaviour with regards to synthesizing IPv6 addresses + from IPv4 addresses SHOULD follow the recommendations given in + Section 3 of [RFC7050], limited to the NAT64 prefixes that have non- + zero lifetime.. When different Pref64 are discovered by using multiple mechanisms, - hosts SHOULD select one source of infromation only. The RECOMMENDED + hosts SHOULD select one source of information only. The RECOMMENDED order is: o PCP-discovered prefixes ([RFC7225]), if supported; o Pref64 discovered via RA Option; o Pref64 resolving IPv4-only fully qualified domain name ([RFC7050]) Note that if the network provides Pref64 both via this RA option and [RFC7225], hosts that receive the Pref64 via RA option may choose to - use it imediately before waiting for PCP to complete, and therefore + use it immediately before waiting for PCP to complete, and therefore some traffic may not reflect any more detailed configuration provided by PCP. 7. Multihoming Like most IPv6 configuration information, the Pref64 option is specific to the network on which it is received. For example, a Pref64 option received on a particular wireless network may not be usable unless the traffic is also sourced on that network. - Similarly, a host connected to a cellular network that povides NAT64 + Similarly, a host connected to a cellular network that provides NAT64 generally cannot use that NAT64 for destinations reached through a VPN tunnel that terminates outside that network. Thus, correct use of this option on a multihomed host generally requires the host to support the concept of multiple Provisioning Domains (PvD, a set of configuration information associated with a network, [RFC7556]) and to be able to use these PvDs. This issue is not specific to the Pref64 RA option and, for example, is quite typical for DNS resolving on multihomed hosts (e.g. a host might resolve a destination name by using the corporate DNS server via the VPN tunnel but then send the traffic via its Internet-facing interface). 8. Pref64 Consistency - Section 6.2.7 of [RFC4861] recommends that routers inspects RAs sent + Section 6.2.7 of [RFC4861] recommends that routers inspect RAs sent by other routers to ensure that all routers onlink advertise the consistent information. Routers SHOULD inspect valid Pref64 options received on a given link and verify the consistency. Detected inconsistencies indicate that one or more routers might be misconfigured. Routers SHOULD log such cases to system or network management. Routers SHOULD check and compare the following information: o set of Pref64 with non-zero lifetime; @@ -348,55 +348,56 @@ The security measures that must already be in place to ensure that Router Advertisements are only received from legitimate sources eliminate the problem of NAT64 prefix validation described in section 3.1 of [RFC7050]. 11. Acknowledgements Thanks to the following people (in alphabetical order) for their review and feedback: Mikael Abrahamsson, Mark Andrews, Brian E - Carpenter, Nick Heatley, Martin Hunek, Tatuya Jinmei, Erik Kline, + Carpenter, David Farmer, Nick Heatley, Martin Hunek, Tatuya Jinmei, + Erik Kline, David Lamparter, Jordi Palet Martinez, Tommy Pauly, Michael Richardson, David Schinazi. 12. References 12.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . + [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, + "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, + DOI 10.17487/RFC4861, September 2007, + . + [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, DOI 10.17487/RFC6052, October 2010, . 12.2. Informative References [I-D.ietf-intarea-provisioning-domains] Pfister, P., Vyncke, E., Pauly, T., Schinazi, D., and W. Shao, "Discovering Provisioning Domain Names and Data", draft-ietf-intarea-provisioning-domains-05 (work in progress), June 2019. [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "DNS Security Introduction and Requirements", RFC 4033, DOI 10.17487/RFC4033, March 2005, . - [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, - "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, - DOI 10.17487/RFC4861, September 2007, - . - [RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J. Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105, DOI 10.17487/RFC6105, February 2011, . [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146, April 2011, .