alt Hacker NewsA NAT is part of a firewall, not a separate thing, so if the firewall is misconfigued, then your NAT may not be working either.
On not running out of (private) IPs, I guess you've never had the fun of having to deal with overlapping ranges (because it isn't the number of IPs that's the issue, it's how the ranges are allocated). While this can still happen on IPv6, there are so many more subnets that this is far less likely.
Also, a key thing that IPv6 makes obvious (which is also true to some extent of IPv4, but that most systems try to avoid showing) is that each link can have multiple IPs (there will be at least one link-local address), and so while your ISP can provide you a public range, you don't need to use it if you do not want to, you can always use an Unique Local Address (ULA - https://en.wikipedia.org/wiki/Unique_local_address), which reduce the chance of overlapping ranges.
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> if the firewall is misconfigued, then your NAT may not be working either.
But in that case, it's very obvious because your access to the WAN side of your router won't work from anywhere except the router itself.
I like this "fail-secure" nature of NAT. If your firewall fails on a network with globally-routable IPv6 addresses, it might not be so obvious as traffic might still flow through.
Why do you think NAT is part of a firewall? NAT and firewall are two completely separate things that can exist independently of each other.
Also overlapping ranges are an orthogonal issue that can occur with IPv6 private network range as well.
IPv6 brings not only bigger address range but also a big bag of other things that one cannot ignore, are complicated and which are often a source of problems. That's why people stick with IPv4 even at the cost of NAT, because the number of things they have to care about is much smaller.