Re: [v6ops] complains about '64::' addresses draft-vf-v6ops-ipv6-deployment

[Alexandre Petrescu <[e-mail]>]

Le 24/03/2021 à 15:36, Gert Doering a écrit :
> HI,
> 
> On Wed, Mar 24, 2021 at 03:32:08PM +0100, Alexandre Petrescu wrote:
>> Le 24/03/2021 à 13:11, Gabor LENCSE a écrit :
>>> I meant that you need to do the address synthesis manually. I 
>>> intended the 64:ff9b::/96 WKP only as an example.
>> 
>> As a side note,  I think that 64:ff9b::/96 prefix might need a
>> 32bit IID, which is probably forbidden by the IPv6 Addressing
>> Architecture RFC 4291 ("For all unicast addresses, except those
>> that start with the binary value 000, Interface IDs are required to
>> be 64 bits long").
> 
> 64:: does start with 000
> 
> And it has no IID at all, not "/32".

I must complain about this, sorry :-)

For some reason - why? - we end up with two kinds of unreachable
addresses: '64::'s and 'fc's (which can also be noted as 'fd's).

They are called "Local-Use IPv4/IPv6 Translation Prefix" and "ULA"s,
which are two different things.

Both these LUTs and ULAs cant go in the Internet - in principle - but
they are distinct spaces.

I wonder why LUT designers didnt use ULAs?

2. These 64:: prefixed addresses might actually _be_ attached to
interfaces, and not just results of algorithms or rt table entries.

I noticed DNS64 resolvers that tell on the Internet that they own such
address, so one would query it from inside that particular network, but
not from the Internet.

I think there might be a misunderstanding here: IANA does not allocate
them but people make it look as if they are allocated.

Also, there might be a problem at IANA as well.

IANA makes some confusing statement about this 64:: space.

For example it says that "64:ff9b::/96" is globally reachable, but when
when I try to reach it from an IPv6-only computer it isnt.  This
'globally reachable' is said on the same web page that says fc00::/7
(ULA) is not globally reachable.
https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml

Maybe someone has a "64::" addresses computer that I could ping6 or
query with an nslookup server command?

Alex

> 
> Gert Doering -- NetMaster
>