Access to the IPv4 net for IPv6-only systems, was: Re: WG Action: Conclusion of IP Version 6 (ipv6)

Randy Bush randy at
Sat Sep 29 00:46:48 UTC 2007

> NAT grew out of need. It didn't grow up in the IETF. We did have a NAT
> WG, to document, define common terminology and guidelines. We took a lot
> of heat for just documenting what was out there. The marketplace
> resulted in the success of NAT. Even if there had been limitless address
> space, it's unlikely NAT would have been avoided.

nat is not a technology, it is the anti-$deity, at least to some. the
ivtf loves to throw out multiple confusing and competing technologies
and say "let the market decide." but it somehow has had very deaf ears
when the market decided nat in a very big way. this is not to say i
would want a nat to marry my brother!

but, ome months back, some wiser heads in the ivtf listened and agreed
that nat-pt (no, alain, i will not be silly and let people force me to
confuse things by calling it something else), is seriously required even
though it is disgusting to us all.  thank you russ and jari; and i am
sure others will climb on the bandwagon and wave flags.

the alternatives are more disgusting, and lack of nat-pt is a serious
impediment to ipv6 deployment, a critical one in a world of ipv4 address
space scarcity.

for an example of the problems of public proxies, as Jeffrey Streifling
said (in wiki),
  o Email/SMTP is a mandatory application
  o Everyone needs to be able to send email to arbitrary recipients,
    i.e. everyone else
  o But, due to SPAM, no one can run an open SMTP relay
  o So all IPv6 sites need to have the ability to SMTP to arbitrary IPv4
  o Therefore everyone needs private dual stack relay until the world is
    all dual stack SMTP


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