- intercepts DNS replies coming back from the ISPs resolvers,
 -- If they return a reply in any form for www.<domain> and
  --- this reply does not include an AAAA record then
  ----- return an AAAA record for an IPv6 address, constructed from a
prefix containing encoded copies of your source address (as the DSL user)
and the destination address (from the original reply, the website) , where
this prefix is routed to a NAT device

- The NAT device, when receiving the IPv6 traffic from the inside, decodes the
Ipv4 addresses encoded within it and sources an IPv4 packet to the decoded
destination address (ports are preserved from the client) , it sources
this packet from the decoded ipv4 source address of the client (which it
impersonates).
-- The NAT must impersonate the Ipv4 source of the original client as not
doing so may break web applications which either load-balance or rely-upon
in some way, the real IPv4 address of the client being preserved (much
like how wikipedia saw the UK reduced to a few IP addresses during the IWF
blocking of their article, we don't want that to happen again)
--- When packets return over the core network, they must pass through the NAT device 
which must make a decision as to whether to either source an Ipv6 packet back to the end-user
(preserving the ports , sourcing from the original encoded address) or simply forwarding the packet
back to the end-user via IPv4 , it is anticipated that all packets translated will be tagged in some form 
such that the decision to translate in reverse (or forward) can be made