v6 adoption is often an all or nothing, because if you run both stacks, you have to ensure they are consistent. While you can reasonably do it on your home LAN, doing it across an entire infrastructure is the worst.
Now you have to make sure all your subnets, routing, VLANs, firewall rules, etc work exactly the same in two protocols that have very little in common.
It is the equivalent of shipping two programs in different languages and maintaining exact feature parity between both at all times.
v4 was built around the idea of multiple free standing networks linked by gateways. v6 was built around the idea of a universal network.
I dont care about what your LAN adress space look like when I'm in my LAN, because we are not in the same v4 network. I am sovereign in my network.
With v6, everyone is effectively in the same network. I have to ask my ISP for a prefix that he will rent me for money even for my LAN. If I want some freedom from said ISP prefix, I am mercifully granted the honor of managing ULA/NAT66 (granted I paid for a fancy router).
Also if I want any kind of privacy, I will have to manage privacy extensions and the great invention of having to use automatically generated, dynamically routed, essentially multiple random IPs per interface. How lucky am I to use such a great new technology.
Seriously v6 was created by nerds in a lab with no practical experience of what people wanted.
It was absolutely not. This is why early companies like Apple and Ford got massive IP allocations - each computer was expected to have a unique IP address.
NAT didn't exist until 14 years after IPv4 was created, in response to the shortage of IPv4 addresses, and in the RFC it is described as a "short-term solution", very clearly stated that his not how the internet is designed to work and it should only be used as a stopgap until we get longer addresses.
I don't think this is what v4 was built around, but rather what v4 turned into.
CIDR wasn't introduced until 1993. NAT in 1994. Both to handle depleting IP addresses.
> With v6, everyone is effectively in the same network.
Just like IPv4.
> I have to ask my ISP for a prefix that he will rent me for money even for my LAN.
Just like IPv4, if you need a static address.
> If I want some freedom from said ISP prefix, I am mercifully granted the honor of managing ULA/NAT66 (granted I paid for a fancy router).
Compared with IPv4, where if you want some freedom from said ISP subnet, you are mercifully granted the honor of managing RFC-1918 addresses/NAT (granted you paid for a router that doesn't screw it up).
> Also if I want any kind of privacy, I will have to manage privacy extensions
...which are enabled by default nearly universally
> and the great invention of having to use automatically generated, dynamically routed, essentially multiple random IPs per interface.
Make up your mind. Are rotating, privacy-preserving addresses good or bad? The way it works in real life, not in the strawman version, is that you (automatically!) use the random addresses for outgoing connections and the fixed addresses for incoming.
