RFC 3046 (rfc3046) - Page 1 of 14

DHCP Relay Agent Information Option

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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.




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