I disagree. What problem does NAT solve, other than allowing people to cut corners and not deploy IPv6?

> I disagree. What problem does NAT solve, other than allowing people to cut corners and not deploy IPv6?

It by default ensures that machines inside a network are not reachable from the outside world. It gives you one address to the outside world which made IP blocks for abuse work quite well and enabled a lot of other users.

Sure, it's a bit of a pain for UDP communication but given the common NAT behaviours not completely terrible. If it was defined a bit clearer NAT would not have been that controversial.

So does a firewall, in a much less complicated way.

NATs are not terribly complex and most consumer grade firewalls are significantly worse than a simple NAT is.

Well, it allowed us to keep growing the internet before we had IPv6, for one thing.

You might want to look at when IPv6 was designed. It's quite a bit older than you might think.

Designed is very different from available in any form. If I couldn't buy a router that supports it with any amount of money, NAT was my only answer. This was the existing state of the world for a long time.

Wasn't IPv6 already out before we ran out of IPv4 addresses? In which case NAT is just a kluge for the lazy who didn't want to deploy IPv6.

One can't control those that must deploy IPv6 first. That's the problem NAT solves. Developing NAT was likely not easy; consider how many implementations f it up anyway.

The main problem it causes is that it breaks the internet: not all peers are routable. It's difficult to think of a greater benefit that offsets that.

> not all peers are routable.

For me that's a core feature of NAT, not something that breaks the internet.

It breaks the internet because it breaks IP - the internet protocol. Segregating devices onto separate networks that are not routable to each other is something that reduces the overall functionality of the internet, not enhances it.

It doesn't help that it's a shitty hack which causes endless lost time either spent wondering why something is broken, or through designing entire protocols just to get around it.

If you consider that "breaking" the internet then many thing break it. That seems like a weird argument to make.

I understand where you're coming from with that – but I can imagine a different Internet, where devices where by default globally routable but firewalled. That could even have affected the current trend towards 'stuff it all in my proprietary cloud system'.