RFC 2230 (rfc2230) - Page 2 of 11

Key Exchange Delegation Record for the DNS

RFC 2230           DNS Key Exchange Delegation Record      November 1997


   reader is assumed to be familiar with the basics of DNS, including
   familiarity with [RFC-1035, RFC-1034].  This document is not on the
   IETF standards-track and does not specify any level of standard.
   This document merely provides information for the Internet community.

1.1 Identity Terminology

   This document relies upon the concept of "identity domination".  This
   concept might be new to the reader and so is explained in this
   section.  The subject of endpoint naming for security associations
   has historically been somewhat contentious.  This document takes no
   position on what forms of identity should be used.  In a network,
   there are several forms of identity that are possible.

   For example, IP Security has defined notions of identity that
   include: IP Address, IP Address Range, Connection ID, Fully-Qualified
   Domain Name (FQDN), and User with Fully Qualified Domain Name (USER
   FQDN).

   A USER FQDN identity dominates a FQDN identity.  A FQDN identity in
   turn dominates an IP Address identity.  Similarly, a Connection ID
   dominates an IP Address identity.  An IP Address Range dominates each
   IP Address identity for each IP address within that IP address range.
   Also, for completeness, an IP Address identity is considered to
   dominate itself.

2. APPROACH

   This document specifies a new kind of DNS Resource Record (RR), known
   as the Key Exchanger (KX) record.  A Key Exchanger Record has the
   mnemonic "KX" and the type code of 36.  Each KX record is associated
   with a fully-qualified domain name.  The KX record is modeled on the
   MX record described in [Part86]. Any given domain, subdomain, or host
   entry in the DNS might have a KX record.

2.1 IPsec Examples

   In these two examples, let S be the originating node and let D be the
   destination node.  S2 is another node on the same subnet as S.  D2 is
   another node on the same subnet as D.  R1 and R2 are IPsec-capable
   routers.  The path from S to D goes via first R1 and later R2.  The
   return path from D to S goes via first R2 and later R1.

   IETF-standard IP Security uses unidirectional Security Associations
   [RFC-1825].  Therefore, a typical IP session will use a pair of
   related Security Associations, one in each direction.  The examples
   below talk about how to setup an example Security Association, but in
   practice a pair of matched Security Associations will normally be



Atkinson                     Informational