Around here (USA) ISPs still give publically routables IPs to customers, and the customer is responsible for running their own NAT if they want to have multiple

Around here (USA) ISPs still give publically routables IPs to customers, and the customer is responsible for running their own NAT if they want to have multiple devices on their network. Most routers support port forwarding, which allows those households to have publically routable TCP or UDP ports on any device within the network. In theory UPNP allows devices to set this up seemlessly. It has become less common with the rise of clouds. But it used to be common for multiplayer games to be done by one player setting up their instance as a server.