Steven Bellovin wrote: > I do not agree. I remember discussing the concept with folks, a couple > of years before that; we agreed that NATs would be very challenging > because of the need for protocol-dependent packet inspection and > modification. Add to that an underestimate of how long it would take > before v6 was adopted, and a gross underestimate of how large the > Internet would be -- remember, IPng happened before the Web explosion -- > and it was very easy to ignore the possibility of NAT, let alone the > renumbering and (questionable) firewall benefits of it. In retrospect, > sure, but in 1993-1994? It was not at all obvious. Underestimate? One of a fatal problem of IPv6 that IPv6 address is 16B long while 8B is a lot more than enough is a result of gross overestimate of how large the Internet would be. RFC1715 killed IPv6. Masataka Ohta