A single PC, with no additional need to subnet, dialing-up from a hotel room may receive its /128 IPv6 address for a PPP style connection as part of a /64 prefix. Read that carefully. The IETF is recommending that every car and cell phone receive /64! That's a reflection of the staggering number of IPv6 addresses that are available. Suddenly, my state-of-the-art smartphone seems woefully inadequate with its paltry single IPv4 address. NAT was one of the great inventions that gave us breathing room when we thought we were running out of IPv4 addresses. How do we use NAT with IPv6? We don't. IPv6 does not support NAT. There are SO many addresses that we simply don't need it. There is, however, an argument that hiding your real IP addresses behind a different IP address is good for security. The counterargument is that this is not really security Chapter 37: IPv6 as much as perceived security through obscurity. There have been many talks about including it into the IPv6 specs, but as of now, nothing has been solidified. There are features called NAT-PT and NAPT-PT that allow you to translate IPv6 to IPv4 addresses (NAPT-PT allows port translation as well), but these are designed as migration tools to help you get off of IPv4. Before NAT existed, everyone got publicly routable IP addresses. IPv6 simply returns us to where we started. Will NAT be included in IPv6? Maybe. I much prefer the idea of a world without NAT, though. Simple Router Configuration Here, I have two routers connected through a switch. R1 has an IPv4 address of 10.0.0.1/24 on f0/0, and R6 has an IPv4 address of 10.0.0.6/24 on fo/o. To establish an IPv6 link-local address on these interfaces, I've done absolutely nothing other than enabling the interfaces (there is an IPv4 address applied, but it doesn't affect this testing): R1 (config)#int fo/o (config-if)#ipv6 address autoconfig Running the show interface command on the revision of code I'm using gives no in- dication of an IPv6 address: R1#sho int fo/o FastEtherneto/o is up, line protocol is up H