[Jool-list] RFC: Limiting EAM algorithm to specific header fields

[Tore Anderson]

* Michael Richardson <mcr at sandelman.ca>

> No, I don't mean multiple gateways into the same DC.
> 
> I mean, how is the hair pinning problem different than if there were
> connections between multiple DC.  It seems that if there is an issue,
> that it's something to do with the outgoing NAT64.

Ah, you mean if the different DCs are served by *differently
configured* SIIT gateways? In particular, using a different RFC6052
translation prefix, and a different set of IPv4 addresses? If so, there
should be no problem at all.

The problem occurs when two IPv6 nodes handled by the same SIIT
instance tries to communicate through it. The IPv6 nodes can very well
be located in different data centres, this doesn't really matter, what
matters is that the source address will be rewritten according to the
EAM rather than RFC6052 mapping, which makes the response packet go
directly rather than through SIIT. That in turn means that the response
will appear to come from a different address than the initial packet
was adressed to, so it is discarded.

Tore