Internet centralization and the original sin of NAT

If the utility and functionality of the server requires those things, then they're required regardless of whether or not that server is internet-facing.

Jill from Elbonia may be always be a threat, but this doesn't mean that Joe from Accounting is not a threat or cannot ever provide a vector for Jill. :)

There was a point in time in the mid-2000s when P2P networking had briefly made running your own server attractive to end-users again. And then the iPhone came out and completely killed any hope of that becoming the norm.

The thing about smartphones is that they are both completely dependent on wireless connections to central servers in order to function and completely unsuitable to operate as servers. If you forced your phone to serve files anyway, your battery would drain quickly and the CPU would be drowning in its own waste heat. You might argue that you could still do non-server things on the phone, but practically speaking, a node that can't handle server tasks is just a leech. P2P networks work on a mutual aid basis; they require the majority of nodes be capable of shouldering traffic or sharing files in order to be a net benefit. If you add, say, tens of millions of new mobile phones to the network, the network will become unusable as any desktop machine gets DDoSed by hordes of phones asking for a babysitter.

So even in the world where IPv6 did to v4 what v4 did to NCP, we'd still ultimately end up with "my files go in the cloud", because clouds are coinventions of smartphones, in the same way that cars are coinventions of suburbs. You can't have one without the other, and once you do have both, they become so economically dominant that others get socially coerced into using them.

Yeah, no.

Working around NAT was trivial for the people who actually cared about it. I was adding port forwarding rules to my parents' router at age 12. Turns out exposing a poorly-configured Windows XP box to the wider interwebs is a Really Bad Idea - and for the same reason UPnP letting random unpatched shady P2P applications do the same is Very Much Not Good.

Let's face it: consumer devices simply aren't secured well enough to let the entire internet poke around in them, and it was even worse a decade or two ago. Decentralization is pointless when it only results in people compromising their own machines, and the people with the skills to set up a 24/7 Linux server in a broom closet won't care about adding some NAT forwarding rules.

Even without NAT, we would've definitely gotten home internet routers firewalled with a default-deny policy on all incoming connections. Exactly the same "manually configure a bypass, or use UPnP" dance blocking you from trivially running a web-available service on your machine, but with a firewall rule rather than a NAT port forward.

It's of course a different story with CGNAT, but that only became a thing well after the internet was already centralized.

> 2. With IPV6 you can have so many IPS that unwanted users can't guess your IP.

In fact you could have an IPv6 address for each user, and if one starts becoming troublesome both revoke account and stop using that address.

You could create a new IPv6 address every millisecond, and it'd take 584,868,233 years to exhaust a IPv6 subnet (/64).