Real World NAT64 deployments

Owen DeLong owen at
Thu Mar 3 23:44:17 CST 2011

HE uses 6in4. 6in4 is basically the same protocol as 6to4, but, with defined
end-points for point-to-point tunneling packets from multipoint to multipoint.

6to4, conversely, uses anycast to identify the tunnel exit point towards the
IPv6 network or to identify the tunnel entry point towards the IPv4 segment.
It depends on encoding the IPv4 address of the local encapsulating host
sending the packet inside of the IPv6 source address in order to be able
to identify the IPv4 destination after encapsulation. For 6to4, one end is
almost always a single specific host which both generates the packets
and does he IPv4 encapsulation.


On Mar 3, 2011, at 2:01 PM, Hammer wrote:

> A little better. So what's the difference between 6to4 and 6in4? Isn't 6in4
> what HE uses?
> -Hammer-
> "I was a normal American nerd."
> -Jack Herer
> On Thu, Mar 3, 2011 at 3:54 PM, William Herrin <bill at> wrote:
>> On Thu, Mar 3, 2011 at 3:41 PM, Hammer <bhmccie at> wrote:
>>> I need a cheat sheet.
>>> nat64
>>> 6to4nat
>>> 6in4nat
>>> etc...
>> 6to4 and 6in4 are not NAT. They're tunnels (VPNs) that allow two IPv6
>> nodes to talk to each other via an IPv4 backbone.
>> nat64 is NAT. It allows IPv6 endpoints to communicate with IPv4 endpoints.
>> nat44 is the IPv4 NAT you're used to.
>> nat444 is carrier NAT (translated once by the customer and once again
>> by the ISP, get it?)
>> --
>> William D. Herrin ................ herrin at  bill at
>> 3005 Crane Dr. ...................... Web: <>
>> Falls Church, VA 22042-3004

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