IPv6 transition mechanism: Difference between revisions

Revision as of 13:39, 24 November 2007

Revision as of 12:56, 12 December 2007

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{{Expand|date=September 2007}}

'''IPv6 translation mechanisms''' are used to allow [[IPv6]]-connected hosts to access [[IPv4]]-connected hosts.

IPv6 Theytranslation mechanisms were first defined in RFC 1933 but this RFC has been obsoleted by RFC 4213.

RFC 2765: defines a mechanism known as ''Stateless IP/ICMP Translation'', or '''SIIT'''.

RFC 3142 defines the '''TRT''' method, or ''Transport Relay Translation''. This is the most common NAT-PT implementation for IPv6 transition.

== SIIT ==

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Basically SIIT describes a method by which a [[router]] interprets an [[IPv4#Header|IPv4 header]] and creates a parallel [[IPv6#IPv6_packet|IPv6 header]] with equivalent information and the inverse equivalent operation of converting an [[IPv6#IPv6_packet|IPv6 header]] into an [[IPv4#Header|IPv4 header]]. The actual means of converting an [[IP_address|IPv4 address]] to an [[IP_address|IPv6 address]] or vice-versa may vary, and the means by which the routing occurs is described as unspecified in the RFC.

Due to the method in which SIIT operates it is not a sufficient migration mechanism in that it is incapable of coordinating more than two unique addresses on either side. This means that every IPv6 host would be required to have a globally routable IPv4 address as well.

== NAT-PT ==

'''NAT-PT''', or ''Network Address Translation/Protocol Translation'', was(or simply '''NAT-PT''') is defined in RFC 2766. It willis attempttypically DNSused AAAA-Ain recordconjunction translationwith ona itsDNS-ALG own, but this makes it very difficult to implement, and few implementations are available (as of 2007)implementation.

=== ImplementationsNAPT-PT ===

While almost identical to NAT-PT, ''Network Address Port Translation + Protocol Translation'' which is also described in RFC 2766 adds translation of the ports as well as the address. This is done primarily to avoid two hosts on one side of the mechanism from using the same exposed port on the other side of the mechanism, which could cause application instability and/or security flaws.

*[http://www.merlinux.org/natpt/ Implementation for The Click Modular Router Project]

== TRT ==

'''TRT''', or ''Transport Relay Translation'', was defined in RFC 3142. This is the most common form of SIIT,NAT-PT/NAPT-PT but it relies on DNS forwardingtranslation forbetween AAAA- and A recordrecords translationknown as ''DNS-ALG'' as defined in RFC 2694.

== Translation Mechanisms ==

=== TRT Implementations ===

*[[faithd]]: BSD-based static TRT implementation

*'''pTRTd''': [http://www.litech.org/ptrtd/ pTRTd];: attemptAttempt at TRT for Linux.

*[http://foxmoxie.net/?action=articles&sa=viewarticle&articleid=5 STRATA]: Commercial TRT/NAPT-PT routers.

*[http://www.merlinux.org/natpt/ Click NATPT]: Implementation for The Click Modular Router Project]

=== DNS-ALG Implementations ===

*'''[[totd''']]: DNS translator for BSD & Linux

=== Implementations ===

*[[faithd]]: BSD-based TRT

*'''totd''': translator for BSD & Linux

*'''pTRTd''': [http://www.litech.org/ptrtd/]; attempt at TRT for Linux.

== Other Mechanisms ==

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*[http://www.join.uni-muenster.de/Dokumente/Howtos/Howto_TRT.php?lang=en TRT Howto from 2003]

*[http://student.grm.hia.no/master/ikt03/ikt6400/g03/filer/Hovedprosjekt_G3.doc IPv6 - Prospects and problems: a technical and management investigation into the deployment of IPv6]

*[http://foxmoxie.net/ Foxmoxie Networks] - A manufacturer of SIITTRT/NAPT-PT routers.

== References ==