Network Working Group Vijayabhaskar A Kalusivalingam Internet-Draft Senthil K Balasubramanian Expires: August 2004 Hewlett-Packard Feb 2004 DHCPv6 Support for Remote Boot draft-ietf-dhc-dhcpv6-opt-rboot-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 August 2004. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract This document provides new DHCPv6 (Dynamic Host Configuration protocol version 6) options for clients, to obtain information about FTP (Trivial File Transfer Protocol) servers and bootfiles needed for booting. 1. Introduction Network booting is widely used mechanism for booting up of the clients. The clients contact the TFTP server to download the bootfiles for bootup. The advantages of using network booting are; softwares will be in central server and requires maintenance at only one location rather than maintaining individual systems separately. Also, switching between different operating systems becomes easy when network booting is being used. In some cases, the nodes may need multiple bootfiles also. The additional boot files may be used as supporting software for the boot image. Different Operating System Vijay, Senthil Expires Aug, 2004 [Page 1] Internet-Draft DHCPv6 support for Remote Boot Feb 2004 vendors use different way of handling this. Single TFTP server for huge number of diskless clients is prone to single point of failure. So, Multiple TFTP servers are needed for high availability. DHCPv6 (Dynamic Host Configuration Protocol Version 6) provides a framework for passing configuration information for hosts on an IPv6 network. However, DHCPv6 does not provide a way to send information about TFTP server address and bootfile names. This document defines two options, Remote boot option and Remote Boot parameter option to provide information about TFTP servers and bootfile names to the clients. These options are required for the clients, which are booting over a network. 2. Requirements 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 RFC 2119 [2] 3. Terminology This document uses terminology specific to IPv6 and DHCPv6 as defined in "Terminology" section of the DHCPv6 specification [1]. 4. Remote Boot Option The Remote Boot Option is used to carry the parameters needed for remote boot of the DHCPv6 clients. Using the information provided by this option, the DHCPv6 clients will bootp up. This will be mainly used by the clients, which are booting using remote boot server. The format of the Remote Boot Option is as shown below: 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_REMOTE_BOOT | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . Remote-Boot-options . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code: OPTION_REMOTE_BOOT (tbd) option-len: Length of the 'Remote-Boot-options' fields in octets; Remote_Boot-options: Options associated with the Remote Boot Option. The Remote Boot option encapsulates those options that are specific to remote boot. This document defines one such option called Remote Boot Parameters Option. Multiple Remote Boot Parameters Options can appear in this option. This option is defined in the Section 5. Vijay, Senthil Expires Aug, 2004 [Page 2] Internet-Draft DHCPv6 support for Remote Boot Feb 2004 5. Remote Boot Parameters Option The Remote Boot Parameters Option is used by the server to convey the client about the TFTP Server IPv6 address and list of boot files needed for booting of the clients. The clients are supposed to contact the TFTP Server, obtain the boot files one by one and boot up using these files. 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_REMOTE_BOOT_PARAMS | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | TFTP Server (IPv6 address) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . Boot Files . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code: OPTION_REMOTE_BOOT_PARAMS (tbd) option-len: Length of the 'TFTP Server' (16 bytes) + 'Boot Files' in Octets; Boot Files: One or more Boot File names in the NVT-ASCII string format. Each file name should be NULL terminated. They should be represented as fully qualified directory-path name. If multiple boot files are provided by the server, then, they should appear in the order of their execution in the client. The first appearing boot file name should be downloaded and executed first for boot up, then the next and so on. This option MUST appear only in the Remote Boot Option. If multiple Remote Boot Parameters Options are present in the Remote Boot Option, then the clients MUST treat them as an ordered list. The server MAY list them in the order of preference. 6. Appearance of these options The Remote Boot Option MUST NOT appear in other than the following messages: Solicit, Advertise, Request, Renew, Rebind, Information-Request and Reply. The option number of Remote Boot option MAY appear in the Option Request Option [1] in the following messages: Solicit, Request, Renew, Rebind, Information-Request and Reconfigure. The Remote Boot Parameters Option MUST appear only in the Remote Boot Option. Vijay, Senthil Expires Aug, 2004 [Page 3] Internet-Draft DHCPv6 support for Remote Boot Feb 2004 7. Security Considerations The Remote Boot Option may be used by an intruder DHCPv6 server to cause DHCPv6 clients to contact rogue TFTP server (or) to send invalid file names. This will make booting up of DHCPv6 clients to fail. This will have a greater impact, if the clients are running some time critical applications. It has a direct impact on the security of the networks, if the clients are running any security applications. To avoid attacks through this option, the DHCP client SHOULD use authenticated DHCP (see section "Authentication of DHCP messages" in the DHCPv6 specification [1]). 8. 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 [1]. Option Name Value Described in OPTION_REMOTE_BOOT tbd Section 4 OPTION_REMOTE_BOOT_PARAMS tbd Section 5 9. Normative References [1] Bound, J., Carney, M., Perkins, C., Lemon, T., Volz, B. and R. Droms (ed.), "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 10. Informative References [3] K. Sollins, The TFTP Protocol (Revision 2), RFC 1350, July 1992. Authors' Addresses Vijayabhaskar A Kalusivalingam Hewlett-Packard STSD-I 29, Cunningham Road Bangalore - 560052 India Phone: +91-80-22053085 E-Mail: vijayak@india.hp.com Vijay, Senthil Expires Aug, 2004 [Page 4] Internet-Draft DHCPv6 support for Remote Boot Feb 2004 Senthil K Balasubramanian Hewlett-Packard STSD-I 29, Cunningham Road Bangalore - 560052 India Phone: +91-80-22053103 E-Mail: ksenthil@india.hp.com 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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