How NAT traversal works (2020)
<i>> (NATs do not enhance security in any meaningful way, but that’s a rant for another time.)</i><p>Eh, I'm not sure I agree. People plug all kinds of weird and wonderful crap into their home networks, they turn off their Windows firewall and allow connections to RPC ports, all sorts of nonsense. The main factor that prevents even more stuff being exposed to the internet than now (and there's a <i>lot</i> exposed already) is the prevalence of IPv4 NAT devices.<p>OK, UPnP is a thing, and NATs aren't firewalls, but in practice NATs do look and feel enough like a firewall to be at least somewhat useful to the average home user.