NAT64 Handoff
draft-dupont-6man-nat64handoff-00

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Last updated 2019-04-03
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Network Working Group                                          K. Dupont
Internet-Draft                                             April 4, 2019
Intended status: Standards Track
Expires: October 6, 2019

                             NAT64 Handoff
                   draft-dupont-6man-nat64handoff-00

Abstract

   This document describes a NAT64 extension which allows IPv4 hosts to
   learn the real IP address of hosts which they are communicating with
   and assume responsibility to maintain the authoritative connection
   tracking table.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on October 6, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   described in the Simplified BSD License.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Communication model . . . . . . . . . . . . . . . . . . . . .   3
   4.  Packet formats  . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Packet formats from NAT64 to server . . . . . . . . . . . . .   7
   6.  Packet formats from server to NAT64 . . . . . . . . . . . . .   7
   7.  Multiple connection tracking entry format . . . . . . . . . .   7
   8.  NAT64 operation . . . . . . . . . . . . . . . . . . . . . . .   8
   9.  Token validation  . . . . . . . . . . . . . . . . . . . . . .  10
   10. Server operation  . . . . . . . . . . . . . . . . . . . . . .  11
   11. Server side NAT . . . . . . . . . . . . . . . . . . . . . . .  12
   12. Security Considerations . . . . . . . . . . . . . . . . . . .  13
   13. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   14. Normative References  . . . . . . . . . . . . . . . . . . . .  14
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   Due to shortage of IPv4 addresses various models of NAT are seeing
   widespread usage as a way to reach IPv4-only services.  The use of
   NAT has some drawbacks.  This document aims to address two of those
   drawbacks by providing an extension for NAT64.

   Connection tracking entries on the NAT can be expired due to
   idleness.  When doing such expiry the NAT has no way of knowing if
   the entry was still in use and may cause connections between client
   and server to be interrupted.

   The server doesn't know the real IP address of the client.  For the
   purpose of debugging software bugs and investigating abuse all
   clients using the same NAT device will appear indistinguishable to
   the server.

   This document provides a NAT64 extension which aims to solve these
   two drawbacks by allowing the server to assume responsibility to
   maintain the authoritative version of the connection tracking table
   and allowing the NAT64 to only maintain a cache in which entries can
   be purged without causing connections to be interrupted.

2.  Terminology

   NAT64: A dual-stack host translating TCP and UDP according to
   [RFC6146] and implementing the NAT64 handoff protocol as specified in
   this document.

   Server: An IPv4 host implementing the server component of

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   Client: An IPv6 host which initiates communication through a NAT64
   capable NAT64.

   NAT64 handoff: The UDP based protocol specified in this document to
   exchange connection tracking between NAT64 and server.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
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