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

[Michael Richardson]

Tore Anderson <tore at fud.no> wrote:
    >> 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.

I agree that 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.

I think I need to read your email with the example (which I think was in the
tickets) again.  I'm sorry that I haven't located it again.

I think that if we are having this problem is because we are skipping some
step that would have occured when there were two DCs served by two different
SIITs.

Let me start again with the diagram at:
    http://jool.mx/intro-nat64.html

I think that the problem occurs when A wants to talk to B, but the address
that A has for B is 198.51.100.9 (because the application on A that wants to
talk to B is not v6 able, or the signaling system didn't know that IPv6 was
involved), rather than 2001:db8:4::9.

Am I correct?

--
]               Never tell me the odds!                 | ipv6 mesh networks [
]   Michael Richardson, Sandelman Software Works        | network architect  [
]     mcr at sandelman.ca  http://www.sandelman.ca/        |   ruby on rails    [