DHCP Relay Agent Information Option
RFC 3046
Document | Type |
RFC - Proposed Standard
(January 2001; No errata)
Updated by RFC 6607
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---|---|---|---|
Author | Michael Patrick | ||
Last updated | 2013-03-02 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 3046 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group M. Patrick Request for Comments: 3046 Motorola BCS Category: Standards Track January 2001 DHCP Relay Agent Information Option Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2001). All Rights Reserved. Abstract Newer high-speed public Internet access technologies call for a high-speed modem to have a local area network (LAN) attachment to one or more customer premise hosts. It is advantageous to use the Dynamic Host Configuration Protocol (DHCP) as defined in RFC 2131 to assign customer premise host IP addresses in this environment. However, a number of security and scaling problems arise with such "public" DHCP use. This document describes a new DHCP option to address these issues. This option extends the set of DHCP options as defined in RFC 2132. The new option is called the Relay Agent Information option and is inserted by the DHCP relay agent when forwarding client-originated DHCP packets to a DHCP server. Servers recognizing the Relay Agent Information option may use the information to implement IP address or other parameter assignment policies. The DHCP Server echoes the option back verbatim to the relay agent in server-to-client replies, and the relay agent strips the option before forwarding the reply to the client. The "Relay Agent Information" option is organized as a single DHCP option that contains one or more "sub-options" that convey information known by the relay agent. The initial sub-options are defined for a relay agent that is co-located in a public circuit access unit. These include a "circuit ID" for the incoming circuit, and a "remote ID" which provides a trusted identifier for the remote high-speed modem. Patrick Standards Track [Page 1] RFC 3046 DHCP Relay Agent Information Option January 2001 Table of Contents 1 Introduction........................................... 2 1.1 High-Speed Circuit Switched Data Networks.............. 2 1.2 DHCP Relay Agent in the Circuit Access Equipment....... 4 2.0 Relay Agent Information Option......................... 5 2.1 Agent Operation........................................ 6 2.1.1 Reforwarded DHCP requests............................ 7 2.2 Server Operation....................................... 7 3.0 Relay Agent Information Suboptions..................... 8 3.1 Agent Circuit ID....................................... 8 3.2 Agent Remote ID........................................ 9 4.0 Issues Resolved........................................ 9 5.0 Security Considerations................................ 10 6.0 IANA Considerations.................................... 11 7.0 Intellectual Property Notice........................... 12 8.0 References............................................. 12 9.0 Glossary............................................... 13 10.0 Author's Address...................................... 13 11.0 Full Copyright Statement ............................. 14 1 Introduction 1.1 High-Speed Circuit Switched Data Networks Public Access to the Internet is usually via a circuit switched data network. Today, this is primarily implemented with dial-up modems connecting to a Remote Access Server. But higher speed circuit access networks also include ISDN, ATM, Frame Relay, and Cable Data Networks. All of these networks can be characterized as a "star" topology where multiple users connect to a "circuit access unit" via switched or permanent circuits. With dial-up modems, only a single host PC attempts to connect to the central point. The PPP protocol is widely used to assign IP addresses to be used by the single host PC. The newer high-speed circuit technologies, however, frequently provide a LAN interface (especially Ethernet) to one or more host PCs. It is desirable to support centralized assignment of the IP addresses of host computers connecting on such circuits via DHCP. The DHCP server can be, but usually is not, co-implemented with the centralized circuit concentration access device. The DHCP server is often connected as a separate server on the "Central LAN" to which the central access device (or devices) attach. Patrick Standards Track [Page 2] RFC 3046 DHCP Relay Agent Information Option January 2001Show full document text