Well, yeah, I think I understand what you propose ... but I don&#x27;t really see the point of it. I mean, where is even any significant difference to IPv6?<p>Yeah, you could use the IPv4 routing infrastructure for transport of this new protocol. That&#x27;s also known as tunneling. You can do that with IPv6. Even with automatic assignment of addresses based on IPv4 addresses you already have, that&#x27;s called 6to4. And while that was a nice idea for a transition mechanism (and in the form of 6rd still usefully employed by some ISPs), it&#x27;s not really that useful in the long term, as backbone routers have been IPv6 capable for a long time, simply due to upgrades for higher bandwidths. To take a random example: Peak bandwidth at AMS-IX in 2002 was 12 Gbit&#x2F;s. Now, it&#x27;s 4.2 Tbit&#x2F;s. And they didn&#x27;t do that by multiplying the number of routers by 350.<p>Your analogy to HTTP and TLS also doesn&#x27;t really hold up: Both are protocols that are only implemented at the edge of the network and pretty much only in software that is easy to update, while your suggested extension would have to be implemented from the boundary of the publicly routable IPv4 network outward, which in particular includes hundreds of millions of home routers where even updates to fix security vulnerabilities tend to be difficult to come by.<p>Also, it&#x27;s not actually true that the v4 routing infrastructure wouldn&#x27;t need to know the difference between your server and your router. What if you send a packet to an address that has no route? The router that determines that there is no route sends an ICMP network unreachable to the source address of your packet. How would your translation gateway know which inside address to forward it to? Or how about a fragmentation needed message? Should we break PMTUD for good?