Network Working Group C. Cadar Internet-Draft NEC Expires: June 20, 2005 December 20, 2004 SMTP Option for DHCPv6 draft-cadar-dhc-dhcpv6-opt-smtp-00.txt Status of this Memo This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she become aware will be disclosed, in accordance with RFC 3668. This document may not be modified, and derivative works of it may not be created, except to publish it as an RFC and to translate it into languages other than English. 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 June 20, 2005. Copyright Notice Copyright (C) The Internet Society (2004). Abstract This document describes the SMTP option for Email related configuration information in Dynamic Host Configuration Protocol for IPv6 (DHCPv6). The purpose of the DHCPv6 option for Simple Mail Transfer Protocol (SMTP) Server addresses is to route SMTP messages throughout the Internet to a mail server. Cadar Expires June 20, 2005 [Page 1] Internet-Draft SMTP Option for DHCPv6 December 2004 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements notation & Naming Conventions . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. The Simple Mail Transport Protocol (SMTP) Server Option . . . 3 5. Appearance of these options . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.1 Normative References . . . . . . . . . . . . . . . . . . . . 5 8.2 Informative References . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 5 Intellectual Property and Copyright Statements . . . . . . . . 6 Cadar Expires June 20, 2005 [Page 2] Internet-Draft SMTP Option for DHCPv6 December 2004 1. Introduction This document describes the SMTP option for email related configuration information in Dynamic Host Configuration Protocol for IPv6 [RFC3315]. There is already a SMTP option available in Dynamic Host Configuration Protocol for IPv4 [RFC2132] but since the structure of protocol options for DHCPv6 differs from those used in DHCPv4 there is a need for defining a new SMTP option in DHCPv6. 2. Requirements notation & Naming Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 3. Terminology This document uses terminology specific to IPv6 and DHCPv6 as defined in "Terminology" section of the DHCPv6 specification [RFC3315]. 4. The Simple Mail Transport Protocol (SMTP) Server Option The Simple Mail Transport Protocol (SMTP) Server Option provides a list of one or more IPv6 addresses of SMTP [RFC2821] servers available to the clients for routing SMTP messages throughout the Internet to a mail server. The SMTP servers SHOULD be listed in the order of preference. The format of the SMTP Protocol Servers option is shown in Figure 1. Cadar Expires June 20, 2005 [Page 3] Internet-Draft SMTP Option for DHCPv6 December 2004 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_SMTP_SERVERS | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SMTP server (IPv6 address) | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SMTP server (IPv6 address) | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ........................ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: OPTION_SMTP_SERVERS option-code: OPTION_SMTP_SERVERS (tbd). option-len: Length of the 'SMTP server' fields in octets, it must be a multiple of 16. SMTP address: IPv6 address of SMTP server. 5. Appearance of these options The SMTP server option MUST NOT appear in other than the following messages: Solicit, Advertise, Request, Renew, Rebind, Information-Request and Reply. The option number for these options MAY appear in the Option Request Option [RFC3315] in the following messages: Solicit, Request, Renew, Rebind, Information-Request and Reconfigure. 6. Security Considerations The SMTP server option may be used by an intruder DHCPv6 server to cause DHCPv6 clients to contact a rogue SMTP server, resulting in failure of email sending or in the worst case the intruder may gain access to the content of the email. Also an intruder SMTP server may get the login name and password of the clients which attempt to contact the roque servers. To avoid attacks through these options, the DHCPv6 client SHOULD use authenticated DHCPv6 (see "Authentication of DHCP messages" section Cadar Expires June 20, 2005 [Page 4] Internet-Draft SMTP Option for DHCPv6 December 2004 in the DHCPv6 specification [RFC3315]). 7. IANA Considerations IANA is requested to assign an option code to the following options from the option-code space defined in "DHCPv6 Options" section of the DHCPv6 specification Option Name Value Described in [RFC3315]. OPTION_SMTP_SERVERS option code to be assigned by IANA. 8. References 8.1 Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. 8.2 Informative References [RFC1939] Myers, J. and M. Rose, "Post Office Protocol - Version 3", STD 53, RFC 1939, May 1996. [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. [RFC2821] Klensin, J., "Simple Mail Transfer Protocol", RFC 2821, April 2001. [RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1", RFC 3501, March 2003. Author's Address Cristian Cadar NEC Europe Ltd. Kurfuersten-Anlage 36 Heidelberg 69115 Germany EMail: cristian.cadar@netlab.nec.de URI: http://www.netlab.nec.de Cadar Expires June 20, 2005 [Page 5] Internet-Draft SMTP Option for DHCPv6 December 2004 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights 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; nor does it represent that it has made any independent effort to identify any such rights. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Cadar Expires June 20, 2005 [Page 6]