Andrew G. Malis wrote: > One thing that IPv6 NAT has in advantage to IPv4 NAT is that it can be > stateless, isomorphic, and port transparent by just translating the > upper part of the address, Not at all. Unless the NAT have end to end transparency, statefull trasnration of raw IP addresses in payload is still necessary. Worse, port transparency is not very useful for IPv6, because, transport check sum to be modified may be located in the second or latter fragment, which means stateful reassembly is necessary for IPv6 NAT. And, remember to say IPSEC, which is *REQUIRED* by IPv6. > This allows easy multihoming without needing to punch holes > in ISP address blocks. Wrong. It has nothing to do with NAT nor IPv6. Punch holes are not necessary, if hosts have multiple addresses assigned from ISPs *AND* transport and/or application layer of their peers try all the IP addresses of the hosts, which is the case with DNS/SMTP but not UDP/TCP and almost all the applications. If we can fix transport/application over IP, IPv4 does not need punch holes. Of course, multiple addresses may be held not by individual end hosts but by a middlebox (either IPv4 or Ipv6) and only UDP/TCP of the middlebox may be modified, *IF* you sacrifice end to end transparency. Masataka Ohta _______________________________________________ Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf