[Jool-list] EAM vs 6052

[Tore Anderson]

* Alberto Leiva <ydahhrk at gmail.com>

> > The implementation must (per 6145bis) *support* both, but that
> > doesn't necessarily mean that it requires both to be configured by
> > the user.
> 
> But where's the latter half of that specified?

The way I see it, since such a requirement isn't stated anywhere,
cannot be considered a MUST. On the other hand there is no MUST NOT
either, so I believe both requiring and not requiring pool6 to
beconfigured would be compliant with the specs.

> My point is that this doesn't seem to me like the selling ropes
> situation. We cannot expect the operator to mind intermediary nodes
> with untranslatable addresses while configuring an EAM/SIIT. This
> detail slipped past even the writers of the original SIIT/6052, which
> is the reason why 6791 had to happen later.
> 
> If an operator casually chooses to use the EAMT but no 6052 prefix in
> a situation where every IPv4 address is supposed to be translatable,
> everything will *appear* to work. It's *our* fault if the translator
> starts dropping traffic, not theirs. WE are the ones tying the rope to
> their necks.

You could also argue the same thing about RFC1918 addresses and the use
of the 64:ff9b::/96 well known RFC6052 prefix: Even if the operator has
configured 64:ff9b::/96 as the pool6, you still cannot translate a
packet which contain 64:ff9b::192.168.1.2 (assuming you're compliant
with RFC6052 section 3.1 - I haven't checked that).

Personally, I think that is fine. Translate what you can, drop what you
can not. But if you take the position that if you cannot ensure you can
translate *all* packets, then you refuse to translate *any* packets,
you would need to consider forbidding pool6=64:ff9b::/96 too...

That said, I have no real issue with you making pool6 mandatory, it
doesn't hurt any of my use cases, and if it does in the future I can
easily enough give it some bogus prefix I will then null route in order
to make it happy.

Anyway, you asked for my opinion and you got it - but don't feel
obligated to actually listen to me. :-)

Tore