Dual-Stack Hosts Using "Bump-in-the-Host" (BIH)
RFC 6535

Internet Engineering Task Force (IETF)                          B. Huang
Request for Comments: 6535                                       H. Deng
Obsoletes: 2767, 3338                                       China Mobile
Category: Standards Track                                  T. Savolainen
ISSN: 2070-1721                                                    Nokia
                                                           February 2012

            Dual-Stack Hosts Using "Bump-in-the-Host" (BIH)

Abstract

   Bump-in-the-Host (BIH) is a host-based IPv4 to IPv6 protocol
   translation mechanism that allows a class of IPv4-only applications
   that work through NATs to communicate with IPv6-only peers.  The host
   on which applications are running may be connected to IPv6-only or
   dual-stack access networks.  BIH hides IPv6 and makes the IPv4-only
   applications think they are talking with IPv4 peers by local
   synthesis of IPv4 addresses.  This document obsoletes RFC 2767 and
   RFC 3338.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6535.

Huang, et al.                Standards Track                    [Page 1]
RFC 6535                           BIH                     February 2012

Copyright Notice

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   document authors.  All rights reserved.

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   This document may contain material from IETF Documents or IETF
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   Without obtaining an adequate license from the person(s) controlling
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   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Huang, et al.                Standards Track                    [Page 2]
RFC 6535                           BIH                     February 2012

Table of Contents

   1. Introduction ....................................................4
      1.1. Terminology ................................................5
      1.2. Acknowledgment of Previous Work ............................5
   2. Components of the Bump-in-the-Host ..............................6
      2.1. Function Mapper ............................................8
      2.2. Protocol Translator ........................................8
      2.3. Extension Name Resolver ....................................8
           2.3.1. Special Exclusion Sets for A and AAAA Records .......9
           2.3.2. DNSSEC Support .....................................10
           2.3.3. Reverse DNS Lookup .................................10
           2.3.4. DNS Caches and Synthetic IPv4 Addresses ............10
      2.4. Address Mapper ............................................11
   3. Behavior and Network Examples ..................................11
   4. Considerations .................................................15
      4.1. Socket API Conversion .....................................15
      4.2. Socket Bindings ...........................................15
      4.3. ICMP Message Handling .....................................15
      4.4. IPv4 Address Pool and Mapping Table .......................15
      4.5. Multi-Interface ...........................................17
      4.6. Multicast .................................................17
   5. Application-Level Gateway Requirements Considerations ..........17