Network Working Group F. Templin Internet-Draft Boeing Research & Technology Intended status: Informational November 23, 2009 Expires: May 27, 2010 Dynamic Host Configuration Protocol (DHCPv4) Option for the Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) draft-templin-isatap-dhcp-03.txt Abstract This document specifies a Dynamic Host Configuration Protocol (DHCPv4) option for nodes that implement the Intra-Site Automatic Tunnel Addressing Protocol (ISATAP). Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. 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 27, 2010. 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents Templin Expires May 27, 2010 [Page 1] Internet-Draft ISATAP DHCP Option November 2009 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology and Requirements . . . . . . . . . . . . . . . . . 3 3. ISATAP DHCPv4 Option . . . . . . . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 5. Related Work . . . . . . . . . . . . . . . . . . . . . . . . . 5 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.1. Normative References . . . . . . . . . . . . . . . . . . . 5 8.2. Informative References . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6 Templin Expires May 27, 2010 [Page 2] Internet-Draft ISATAP DHCP Option November 2009 1. Introduction This document specifies a Dynamic Host Configuration Protocol option [RFC2131][RFC2132] for the Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) [RFC5214]. The option encodes configuration information used by clients to initialize the Potential Router List (PRL) as specified in [RFC5214], section 8.3.2. The option format is similar to [RFC3361] and supports publishing of an IPv4 anycast address followed by a list of IPv4 addresses and/or domain names that form the PRL for the ISATAP link. 2. Terminology and Requirements The terminology of ISATAP [RFC5214] applies to this document. The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this document, are to be interpreted as described in [RFC2119]. 3. ISATAP DHCPv4 Option The ISATAP DHCPv4 option encodes an ISATAP IPv4 Anycast address followed by a list of 'M' 4-octet IPv4 addresses followed by a list of 'N' DNS [RFC1035] fully-qualified domain names (FQDNs). The ISATAP DHCPv4 option encodes a sequence of octets using the following format: Code Len M N Any <- IPv4 addr's -> <- FQDN's -> +----+----+----+-----+----+----+----+----+----+----+----+----+----+ | TBD| Len| M | N | Any| a1 | a2 | ...| aM | f1 | f2 | ...| fN | +----+----+----+-----+----+----+----+----+----+----+----+----+----+ Figure 1 In this format, the DHCPv4 option code is followed immediately by a 'Len' octet that indicates the total number of octets that follow within this DHCPv4 option field. The rest of the DHCPv4 option is encoded as follows: o the 'Len' octet is followed immediately by an 'M' octet that indicates the total number of IPv4 addresses that follow the IPv4 Anycast address, o the 'M' octet is followed immediately by an 'N' octet that indicates the total number of FQDNs that follow the list of IPv4 addresses, Templin Expires May 27, 2010 [Page 3] Internet-Draft ISATAP DHCP Option November 2009 o the 'N' octet is followed by a 4-octet IPv4 Anycast address, o the IPv4 Anycast address is followed by a list of 'M' 4-octet IPv4 addresses, o the list of IPv4 addresses if followed by a list of 'N' DNS FQDN's encoded exactly as specified in Section 3.1 of [RFC1035]. (Note: this is the same format specified in Section 3.1 of [RFC1035]). For example, if the server wants to advertise the IPv4 anycast address '192.0.2.1', followed by the IPv4 addresses '192.0.2.3' and '192.0.2.3', followed by the FQDNs "isatap.com", "isatap.org" and "isatap.net", the DHCPv4 option would be encoded as follows (where numeric values are represented as decimal): +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ |TBD| 51| 2 | 3 |192| 00| 02| 01|192| 00| 02| 02|192| 00| 02| +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | 03| 0 | 6 |'i'|'s'|'a'|'t'|'a'|'p'| 3 |'c'|'o'|'m'| 0 | 6 | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ |'i'|'s'|'a'|'t'|'a'|'p'| 3 |'o'|'r'|'g'| 0 | 6 |'i'|'s'|'a'| +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ |'t'|'a'|'p'| 3 |'n'|'e'|'t'| 0 | +---+---+---+---+---+---+---+---+ Figure 2 ISATAP clients MAY use the elements encoded in the ISATAP DHCPv4 option to initialize the PRL as specified in Section 8.3.2 of [RFC5214]. Legacy ISATAP clients may instead silently ignore this option and continue to use their pre-existing PRL initialization methods, i.e., backward compatibility is preserved. Note: when no IPv4 anycast address is to be used for this ISATAP link, the IPv4 Anycast address is encoded as four zero octets (i.e., to represent the value '0.0.0.0'). When a non-zero IPv4 anycast address is included, ISATAP clients MAY use this address as the IPv4 destination address of ip-proto-41 packets that were forwarded into the ISATAP interface via an IPv6 default route. ISATAP routers do not use the IPv4 anycast address as the source address for ip-proto-41 packets; they use their IPv4 unicast address that is listed in the ISATAP PRL instead. This implies that each ISATAP router MUST configure both the IPv4 Anycast address (when the anycast address is non-zero) and an IPv4 unicast address that is added to the PRL. When the length of the ISATAP DHCPv4 Option exceeds 254 octets, the option is encoded as for DHCP long options as specified in [RFC3396]. Templin Expires May 27, 2010 [Page 4] Internet-Draft ISATAP DHCP Option November 2009 ISATAP routers and clients use the unicast IPv4 address in the PRL (i.e., and not the ISATAP IPv4 anycast address) for IPv6 neighbor discovery operations the same as specified in Section 8 of [RFC5214]. 4. IANA Considerations A new DHCPv4 option number for ISATAP is requested. 5. Related Work The ISATAP DHCP option was published in 'draft-templin-isatap-dhcp-00.tx' in February 2003. The use of IPv4 Anycast with ISATAP was published in 'draft-ietf-ngrtans-isatap-00.txt' in March 2001. 'draft-ietf-softwire-ipv6-6rd' presents a similar DHCP option that advertises a 6RD prefix and an IPv4 anycast address. 6. Security Considerations The security considerations in [RFC2131] apply. 7. Acknowledgments The following individuals are acknowledged for their contributions: Jim Bound, Ralph Droms, Mohan Parthasarathy, Pekka Savola. 8. References 8.1. Normative References [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. Templin Expires May 27, 2010 [Page 5] Internet-Draft ISATAP DHCP Option November 2009 [RFC3396] Lemon, T. and S. Cheshire, "Encoding Long Options in the Dynamic Host Configuration Protocol (DHCPv4)", RFC 3396, November 2002. [RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214, March 2008. 8.2. Informative References [RFC3361] Schulzrinne, H., "Dynamic Host Configuration Protocol (DHCP-for-IPv4) Option for Session Initiation Protocol (SIP) Servers", RFC 3361, August 2002. Author's Address Fred L. Templin Boeing Research & Technology P.O. Box 3707 Seattle, WA 98124 USA Email: fltemplin@acm.org Templin Expires May 27, 2010 [Page 6]