Redploying most of 127/8 as unicast public

Sat Nov 20 12:04:38 UTC 2021

Mans Nilsson wrote:

>>> We cope,
>>> because a lot of technical debt is amassed in corporate and ISP /
>>> access provider networks that won't change.
>>
>> Sounds like abstract nonsense.
> 
> No, it is the real reason that we still have v4 around.

Even more than 25 years after IPv6 became a proposed standard?

It merely means IPv6 is not deployable with the real reason.

>> The reality is that application servers only need globally unique
>> and stable IP+Ports.
>>
>> You can address application servers with them.
> 
> If, and that is a big IF, they're designed for that. Hint: They're not,
> and I'm required to deploy technology compatible with older systems and
> systems outside my control.  It would be far easier for me if I could
> continue with the original assumption -- IP addresses are identifiers.

The proper layering, which you insist to ignore, is that IP addresses
are identifiers at the network layer whereas IP+Ports are the
identifiers at above layers.

> I know you will immediately state that if I change everything else except
> the IP addressing scheme at 32 bits plus 16 bits of port space (which in
> and of itself is a change;

It was.

It was the changed made by deploying NAT, which was a lot lot lot
less painful to support IPv6.

 > But I only want to change the addressing layer.

There is no such layer as "the addressing layer".

At the transport layer, connections are addressed by network
addresses and port numbers, which means address there in the
Internet is IP+Port.

I really recommend you to understand proper layering.

 > In your application, that assertion on worseness might be true. In my,
 > where I value the E2E principle higher, no, I think it is not.

So, you are rather a theorist than a practitioner.

However, I'm both of them.

See:

	https://datatracker.ietf.org/doc/html/draft-ohta-e2e-nat-00

to understand that properly architected NAT preserves the so
valuable E2E principle.

For example, I confirmed with my implementation that PORT command
of ftp perfectly works over the E2E NAT gateways.

After finding that, I, as a theorist, totally abandoned IPv6.

						Masataka Ohta