[Info-vax] implementing IPv6 on the internet

[Chris]

On 09/23/16 22:12, Dirk Munk wrote:

 > Great, and how does the router know the IPv6 address of Microsoft, or
 > even better, how does the router know it has to send the packet to the
 > IPv6 address of Microsoft?

The router doesn't have to ask those questions, as it already knows
that it is on a v6 network on the WAN side, having a V6 address from
the isp. Assuming the above, the router will always use v6 for it's
dns request to the isp. The problem I can see with this is that
translating to the local V4 subnet, it may have to use a dummy v4 dns
value in it's reply to the subnet node, perhaps by stripping off some
of the bits, or a hash function, but so long as the router keeps track
of that, it will work, much as tcp connections are tracked through
state tables.

 > The PC did a nslookup remember, the router didn't. The router doesn't
 > know it has to exchange the IPv4 address of microsoft by the IPv6
 > address, how could it? If the PC sends something to an IPv4 address, how
 > can the router know if this destination also has an IPv6 address?

The pc doesn't care. It makes a dns request via the *router* and uses
whatever its given in reply. The fact that that it may or may not be a
genuine address for Google whatever, doesn't matter, so long as there
is agreement in translation terms.

Heck, i'm not designing this stuff, but doesn't look too arduous to
me. There again, if you can only think of stuff to stop it working,
you would never start anything, right ?...

Regards,

Chris