--- 1/draft-ietf-ipsecme-ikev2-redirect-06.txt 2009-04-09 02:12:06.000000000 +0200 +++ 2/draft-ietf-ipsecme-ikev2-redirect-07.txt 2009-04-09 02:12:06.000000000 +0200 @@ -1,18 +1,18 @@ Network Working Group V. Devarapalli Internet-Draft WiChorus Intended status: Standards Track K. Weniger -Expires: September 24, 2009 March 23, 2009 +Expires: October 10, 2009 April 8, 2009 Redirect Mechanism for IKEv2 - draft-ietf-ipsecme-ikev2-redirect-06.txt + draft-ietf-ipsecme-ikev2-redirect-07.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, except to format it for publication as an RFC or to translate it into languages other than English. Internet-Drafts are working documents of the Internet Engineering @@ -24,21 +24,21 @@ 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 September 24, 2009. + This Internet-Draft will expire on October 10, 2009. Copyright Notice Copyright (c) 2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights @@ -287,22 +287,23 @@ N[REDIRECT, IP_R/FQDN_R]} In case the IKE_AUTH exchange involves EAP authentication as described in Section 2.16 of RFC 4306 [2] or multiple authentication methods as described in RFC 4739 [6], the IKE_AUTH exchange is more complicated. The identity presented by the client in the first IKE_AUTH request might be a temporary one. In addition, the gateway might decide to redirect the client based on the interaction with the the AAA server, when EAP authentication is used or the external authentication server, when multiple authentication methods are used. - In such cases, the exact message in which the gateway sends the - REDIRECT payload is TBD. + In such cases, the gateway should send the REDIRECT notification + payload in the final IKE_AUTH response message that carries the AUTH + payload and the traffic selectors. 6. Redirect Messages 6.1. REDIRECT_SUPPORTED The REDIRECT_SUPPORTED payload is included in the initial IKE_SA_INIT request by the initiator to indicate support for the IKEv2 redirect mechanism described in this document. 1 2 3 @@ -347,25 +348,22 @@ ~ Nonce Data ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The 'Next Payload', 'Payload Length', 'Protocol ID', 'SPI Size' and the 'Notify Message Type' fields are the same as described in Section 3.10 of [2]. The 'SPI Size' field MUST be set to 0 to indicate that the SPI is not present in this message. The 'Protocol ID' MUST be set to 0, since the notification is not specific to a particular security association. - If the IP address of the new VPN gateway is sent, the 'Payload - Length' field MUST be set to either '13' or '25' depending on whether - an IPv4 or IPv6 address is sent in the message. If the FQDN of the - new VPN gateway is sent, the 'Payload Length' field is set to the - length of the FQDN plus the fixed fields in the message. The 'Notify + The 'Payload Length' field is set to the length in octets of the + entire payload, including the generic payload header. 'Notify Message Type' field is set to indicate the REDIRECT payload . The 'GW Identity Type' field indicates the type of information that is sent to identify the new VPN gateway. The following values are reserved by this document. 1 - IPv4 address of the new VPN gateway 2 - IPv6 address of the new VPN gateway 3 - FQDN of the new VPN gateway All other values for this field are reserved and MUST NOT be used. @@ -444,20 +442,31 @@ event. However, this may happen if a Home Agent/VPN server is shutdown for maintenance and all clients need to re-establish VPN connections with another Home Agent/VPN server or if the on-path attacker forces all IPsec security associations to expire by dropping all received IKEv2 messages. The use of REDIRECTED_FROM payload is intended to discourage a rogue VPN gateway from redirecting a large number of VPN clients to a particular VPN gateway. It does not prevent such a DoS attack. + Since the redirect message is not always sent as a secure message, it + MUST NOT result in the modification of the PAD entries on the client. + The new gateway, to which the client is redirected to should be + subject to the same authentication and authorization requirements as + the original gateway. To support a scenario where the FQDN of the + gateway is in the client's PAD entry and the client is redirected to + another gateway in the same administrative domain, one can either + configure all the possible gateways from the domain or use a wildcard + entry like, for example, GW*.example.com, in the client's + corresponding PAD entry. + 9. IANA Considerations This document defines four new IKEv2 Notification Message types as described in Section 6. The three Notify Message Types must be assigned values between 16396 and 40959. o REDIRECT_SUPPORTED o REDIRECT o REDIRECTED_FROM @@ -466,21 +475,22 @@ The use of anycast address with IKEv2 was first described in [7]. It was then added to an early draft version of RFC 5026 and later removed before the RFC was published. Therefore the authors of [7] and RFC 5026 are acknowledged. Thanks to Pasi Eronen, with whom the solution described in this document was extensively discussed. Thanks to Tero Kivinen for suggesting the use of REDIRECTED_FROM payload and other comments which helped improve the document. The authors would also like to thank Yaron Sheffer, Sunil Kumar, Fan Zhao, Yoav Nir, Richard - Graveman, and Arnaud Ebalard for their reviews and comments. + Graveman, Kanagavel Rajan, Srini Addepalli, and Arnaud Ebalard for + their reviews and comments. 11. References 11.1. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", RFC 4306, December 2005.