DHC Working Group Internet Draft J. Aiello draft-aiello-dhc-appliance-class-00.txt Sylantro Systems Expires: July 2001 January 2001 Appliance Class Identifier Option for DHCP 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 rendered obsolete 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. Table of Contents 1. Abstract........................................................2 2. Conventions used in this document...............................2 3. DHCP Terminology................................................2 4. Overview........................................................2 5. The Appliance Class Identifier Option...........................3 7. Security Considerations.........................................3 9. Acknowledgements................................................4 10. Author's Addresses.............................................4 Aiello Informational - Expires July 2001 1 Appliance Class Identifier Option January 2001 1. Abstract The Appliance Class Identifier option is used by a Dynamic Host Configuration Protocol (DHCP) client to identify the type of appliance it belongs to. The information contained in this option is an opaque field that represents the appliance class of which identifies the type of client. Based on this class, a DHCP server selects the appropriate address pool to assign an address to the client and the appropriate configuration parameters. This option should be selected by the appliance manufacturer and included in the DHCP Discover/Request messages. 2. Conventions used in this document 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 RFC-2119 [1]. 3. DHCP Terminology - "DHCP client" A DHCP client or "client" is an Internet host using DHCP to obtain configuration parameters such as a network address. - "DHCP server" A DHCP server is an Internet host that returns configuration parameters to DHCP clients. - "Appliance" An appliance is a DHCP client that not what is a special function device such as an IP phone. - "Appliance manufacturer" The entity who manufacturers the appliance or has it manufactured in their name. 4. Overview New and emerging IP based appliances (devices) may need to be identified by DHCP servers differently than other DHCP clients. These new appliances may require IP addresses and DHCP supplied options different than other DHCP clients. Network devices such as routers and firewalls will require special handling of some appliances. For example, an IP phone (appliance) may require an IP address that will not be translated by the router and may require unique options such as a Call Agent server IP address or a DNS Aiello Informational - Expires July 2001 2 Appliance Class Identifier Option January 2001 server IP address used exclusively for Voice over IP networks. These appliances may need to have separate IP address pools allocated just for the various appliances. The client identifies itself as a specific appliance class, by this new option, to the DHCP Server. The DHCP shall issue an IP address allocated for that appliance type from the DHCP server. This ensures no computer, printer, etc. receives an IP address allocated for a specific appliance type. The DHCP server should support multiple Appliance Classes. 5. The Appliance Class Identifier Option The code for this option is TBD. The Appliance Class Identifier is used by the DHCP Client to optionally identify the appliance class it represents. A DHCP server uses the Appliance Class Identifier to choose the IP address pool it allocates an IP address from and to select any other appliance specific configuration option(s). This option carries only one Appliance Class Identifier. The DHCP server MUST return the Appliance Class Identifier in the DHCP offer-s. The DHCP client must reject the DHCP offer if it does not contain the Appliance Class Identifier. The format of this option is as follows: Code Len Value +-----+-----+-------------------------------------+ | TBD | N | Appliance Class Data | +-----+-----+-------------------------------------+ A server not equipped to interpret the appliance class should ignore it. The server should report the unmatched class event. 6. IANA Considerations Option TBD has been assigned by IANA for this option. 7. Security Considerations DHCP currently provides no authentication or security mechanisms. Potential exposures to attack are discussed is section 7 of the protocol specification. This lack of authentication mechanism means that a DHCP server cannot check if a client or user is authorized to use a given appliance Aiello Informational - Expires July 2001 3 Appliance Class Identifier Option January 2001 class. This introduces an obvious vulnerability when using the appliance class option. For example, if the appliance class is used to give out a special parameter (e.g., a particular call agent server), there is no way to authenticate a client and it is therefore impossible to check if a client is authorized to use this parameter. 8. References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 [2] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [3] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. [4] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [5] Stump, G., "User Class Option for DHCP", RFC 3004, November 2000. 9. Acknowledgements The author would like to thank Eric Nielson for his input and contribution. 10. Author's Addresses Joe Aiello Sylantro Systems 910 East Hamilton, Suite 300 Phone: 1-408-626-3032 Campbell, CA USA Email: joe.aiello@Sylantro.com Aiello Informational - Expires July 2001 4