1. Introduction

   In many remote access scenarios, a mechanism for making the remote
   host appear to be present on the local corporate network is quite
   useful.  This may be accomplished by assigning the host a "virtual"
   address from the corporate network, and then tunneling traffic via
   IPsec from the host's ISP-assigned address to the corporate security
   gateway.  In IPv4, Dynamic Host Configuration Protocol (DHCP) [3]
   provides for such remote host configuration. This document explores
   the requirements for host configuration in IPsec tunnel mode, and
   describes how DHCPv4 may be leveraged for configuration.

1.1. Terminology

   This document uses the following terms:

   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 or "server" is an Internet host that returns
         configuration parameters to DHCP clients.

1.2. Requirements language

   In this document, the key words "MAY", "MUST, "MUST NOT", "optional",
   "recommended", "SHOULD", and "SHOULD NOT", are to be interpreted as
   described in [1].