Network Working Group F. Templin Internet-Draft Nokia Expires: May 25, 2004 November 25, 2003 Applicability of ISATAP for NOID draft-templin-isnoid-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http:// www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on May 25, 2004. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document describes the operation of the NOID multihoming proposal on nodes with ISATAP interfaces. It uses the global DNS as an extension of the ISATAP Potential Router List (PRL) and ISATAP link-local addresses as next-hop addresses for IPv6 routes. 1. Introduction This document describes the operation of the NOID multihoming proposal [NOID] on nodes with ISATAP interfaces [ISATAP]. It uses the global DNS as an extension of the ISATAP Potential Router List (PRL) ([ISATAP], section 6.1) and ISATAP link-local addresses as next-hop addresses for IPv6 routes. Templin Expires May 25, 2004 [Page 1] Internet-Draft Applicability of ISATAP for NOID Multihoming November 2003 In particular, any peer node that has a Fully-Qualified Domain Name (FQDN) in the global DNS that resolves to a list of both AAAA and A records (and indicates participation in the NOID protocol) is considered a Potential Router for ISATAP. The question of whether the node is an actual router is determined by sending IPv6 Router Solicitation messages and getting an IPv6 Router Advertisement back [RFC2461]. 2. Assumptions This document makes the same assumptions as stated in ([NOID], section 1.2: "The main technical assumptions this proposal makes it that the DNS infrastructure can be used for verification of the relationship between locators on both the initiator of communication and the responding peer. In particular, it assumes that getting DNS reverse maps (ip6.arpa) populated for the hosts that wish to take advantage of multihoming will not be a significant problem." In addition, this document assumes that nodes with advertising ISATAP interfaces will arrange to have both AAAA and A records added to the DNS for their FQDNs. 3. Terminology The terminology of [RFC1122],[RFC2461], [NOID], and [ISATAP] applies to this document. 4. NOID Context Establishment Using ISATAP As described in ([NOID], section 3) it is assumed that the DNS maintains consistent forward and reverse maps for hosts that support the protocol. The following specific actions are taken by initiating and responding NOID peers with ISATAP interfaces during context establishment: When a host initiates a connection, it first looks up the FQDN of the target peer in the DNS. If the DNS returns both AAAA and A records, and an indication that the NOID protocol is supported, the initiator assumes that the target peer is a dual-stack (IPv6/IPv4) router that supports both the NOID protocol and ISATAP. In this sense, the initiator assumes that the target peer is a member of the ISATAP Potential Router List (PRL). Next, if default or more-specific routes for the IPv6 addresses returned by the DNS do not exist, the initiator uses the IPv4 addresses from the A records to construct ISATAP link-local addresses Templin Expires May 25, 2004 [Page 2] Internet-Draft Applicability of ISATAP for NOID Multihoming November 2003 ([ISATAP], section 4.1) for use as the IPv6 next-hop toward the IPv6 addresses. Assuming the initiator has an enabled ISATAP interface, it next sends one or more "modified" IPv6 Router Solicitation messages to one of the peer's ISATAP link-local unicast addresses as described in ([RFC2461], section 6.3.7). The Router Solicitations are "modified" in the sense that they carry a special code (TBD) to indicate that ONLY Route Information Options ([RPREF], section 2.3) are desired in returned Router Advertisements. If the initiator receives an IPv6 Router Advertisement from the peer, it verifies that the prefixes advertised in Route Information Options match the IPv6 addresses that were discovered from the DNS FQDN lookup. If the set of prefixes in the Router Advertisement exactly match the addresses discovered from the DNS, the initiator deems the peer an authentic ISATAP router and adds host routes to its IPv6 routing table for each of the IPv6 addresses, using the ISATAP link-local address as the next-hop address. Otherwise, the peer is deemed untrustworthy. Next, the initiator performs a 3-way state creation exchange with the responder as specified in [NOID], section 4.1). (Note that this process MAY carry ULP packets as piggybacked messages.) At some time during or after this context creation 3-way handshake, the responding peer will perform a reverse-DNS lookup on one of the initiator's IPv6 addresses in the ip6.arpa domain, i.e., as an inverse operation of the DNS lookup originally performed by the initiator. The responder uses the information returned by the DNS to validate the locators used by the initiating host and optionally authenticate the initiator by performing a Router Solicitation/Router Advertisement exchange as described above. 5. Other Considerations All other protocol specifications in [NOID] and [ISATAP] are followed exactly. Additionally, first-pass path MTU discovery can be piggybacked onto the Router Solicitation/Router Advertisement process. 6. IANA Considerations Future versions of this document will instruct the IANA to either allocate a new IPv6 Neighbor Discovery option type or to allocate bits in the existing IPv6 Router Solicitation format to signify the type of information being solicited. 7. Security considerations Security considerations are discussed in the normative references. Templin Expires May 25, 2004 [Page 3] Internet-Draft Applicability of ISATAP for NOID Multihoming November 2003 8. Acknowledgements TBD Normative References [ISATAP] Templin, F., Gleeson, T., Talwar, M. and D. Thaler, "Intra-Site Automatic Tunnel Addressing Protocol", draft-ietf-ngtrans-isatap (work in progress), October 2003. [NOID] Nordmark, E., "Multihoming without IP Identifiers", draft-nordmark-multi6-noid (work in progress), October 2003. [RFC1122] Braden, R., "Requirements for Internet Hosts - Communication Layers", STD 3, RFC 1122, October 1989. [RFC2461] Narten, T., Nordmark, E. and W. Simpson, "Neighbor Discovery for IP Version 6 (IPv6)", RFC 2461, December 1998. [RPREF] Draves, R. and R. Hinden, "Default Router Preferences, More-Specific Routes, and Load Sharing", draft-ietf-ipv6-router-selection (work in progress), June 2002. Author's Address Fred L. Templin Nokia 313 Fairchild Drive Mountain View, CA 94110 US Phone: +1 650 625 2331 EMail: ftemplin@iprg.nokia.com Templin Expires May 25, 2004 [Page 4] Internet-Draft Applicability of ISATAP for NOID Multihoming November 2003 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. 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