[arin-ppml] About NAT-PT.... (Re: Fantasyland)

Iljitsch van Beijnum iljitsch at muada.com
Fri Aug 29 05:13:58 EDT 2008

On 29 aug 2008, at 0:07, Alain Durand wrote:

> I read a lot of fantasy about NAT-PT those days, like it is going to  
> be the
> silver bullet that will make this all problems go away...
> NAT-PT is a v6 to v4 translator. Which mean, it only helps if your  
> internal
> network is... v6. If you have any device in there that cannot do  
> IPv6 and
> need to talk to the rest of the universe (think IP-webcam, gaming  
> device,
> windows box prior to vista, load balancer, IDS, firewall, IMS, xyz
> server,.... NAT-PT is *not* a solution for you. Nor would be any of  
> its
> replacement candidates.

> Dual-stack lite (see
> http://tools.ietf.org/html/draft-durand-dual-stack-lite-00) might be a
> better approach in that space. It is being standardized by IETF in the
> softwire working group.

Sorry for overquoting. Note that dual stack light (plz run a spell  
check on your title, Alain!) is just a clever way to do two things:

- make life for ISPs easier so they don't have to route RFC 1918 space  
- make life for end-users easier so they can keep their IPv4-only  
stuff and don't have to go through multiple NATs

Apart from that it's still basically ISP-operated NAT with all the  
downsides that that entails. Which includes no easy and reliable way  
to make incoming connections work: on a good day VoIP that conforms to  
the latest IETF standards may work, but no webcams and probably very  
little BitTorrent until they start using completely new NAT traversal  

So you still want IPv6 for that webcam and most of your peer-to-peer  

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