> Most security conscious operators would only allow IPv4 instead of IPv6.
I strongly disagree. That's obsolete knowledge, thrown around by people who want to be considered security conscious but haven't actually updated their knowledge in many years. A statement with similar implications might be "security conscious operators require their users to rotate their passwords monthly", which is what a lot of people use to think a decade ago, and now what it really communicates is that you're talking to a dinosaur.
But IPv6 is complex and inherently globally accessible. Yes, NAT IS not supposed to be a firewall but it works like one nonetheless in many cases.
IPv6 will never replace IPv4 because it is a different protocol rather than merely a new version. The name is a lie.
> IPv6 is... inherently globally accessible.
No, it's not. If you really want a NAT there is no reason you can't use a NAT with ipv6. In fact, it can work even better because instead of using a random port for the translation, you can use a random ip address for each connection.
A random ip address that is globally reachable?
Why would it be reachable? It might be name-able but that doesn't imply reachable.
You're conflating the two parts of NAT: address translation and inbound filtering. A router can block any inbound traffic coming from WAN, even if the IPv6s on the LAN side are public.
In fact, hole punching for IPv4 shows this distinction. By default inbound traffic is blocked, but as soon as private host has opened up a connection, it is (indirectly) reachable and nameable (via the routers public IP + port).
BTW, static IPv4 NAT with public addresses on both sides exists as well.
Addressable means routable. Otherwise the distinction between a Public and Private address becomes one of firewall rules rather than a meaningful property of the IP Address.
And as you say, hole punching is still “PUBLIC IP” + port. Not an IP and any port you fancy unless the firewall was configured correctly.
Maybe I am wrong, maybe you’re confused, maybe IPv6 is just rubbish. Maybe all 3.
What do you mean globally accessible? All the devices on my network have global IPv6 addresses for the last 5 years - since my ISP enabled IPv6 but none of them are accessible unless I configure it.
Very weird take, and not supported by facts or evidence, but OK.
Do you ever wonder if most people don’t “see the facts” and after almost 3 decades and so much the adoption at 50% might mean to consider if the technology is just rubbish?