I also strongly like NAT. In roughly descending order:<p>1) It fails safe. Virtually all device misconfigurations result in failure to pass traffic, rather than being passed accidentally.<p>2) You get full control of your external signature (at that protocol level). When Comcast and AT&amp;T realize that they can charge for more than a single &#x2F;128 on their consumer networks we&#x27;ll see a lot of wailing and gnashing of teeth on &#x2F;r&#x2F;technology, and it will be completely inane to those of us that saw the same companies attempt the same BS with NAT detection in the late 90s.<p>3) I would like to be able to implement dual stack in networks that I&#x27;m responsible for with as much similarity as possible. Having to reason independently more than needed about how IPv4 and IPv6 behave is needless difficulty.<p>4) IPv6 allocations today are asininely large. We&#x27;re going to have 30-45 years of overallocation and then be out again, and in the interim we&#x27;ll have a whole host of new braindead protocols in the manner of FTP and VOIP. The collective lessons we&#x27;ve learned about NAT will have (for all intents and purposes) been lost and we&#x27;ll get a bunch of new shoddy hacks for dealing with them (passive FTP and NAT-T).<p>5) If it&#x27;s a useful tool, by the user&#x27;s estimation, why can&#x27;t I have it? The internet grew up on what amounted to &quot;be a good peer and we can all get along&quot;, but on this specific topic it quickly dissolves into STOP LIKING THINGS I DONT LIKE, YOU CAN&#x27;T HAVE IT, I&#x27;M TELLING THE IETF.