[tolien]

No they wouldn't. UPnP is not requisite, certainly not standard, or necessarily built-in. For example, the router I've got doesn't implement UPnP. It's not unusual for it to be disabled, because it's a security issue that something with no authentication can punch enduring holes out through NAT. It's also irrelevant in a scenario where the ISP's using CGNAT.

I'm sure the Switch deals with conflict resolution with multiple consoles on the same network too but shrug it's another example of how NAT is a pain and also contradicts your assertion that incoming connections would be a breach of ISP ToS [1].

Edit: A quick Google suggests the Switch originally didn't support UPnP, and the Switch 2 now supports IPv6.

1: https://news.ycombinator.com/item?id=46484604

[DrewADesign]

Ok, so it didn’t even need upnp then. Are you talking about using their LAN head-to-head feature across the internet? Or perhaps all the times I used my switch on various networks to play head-to-head games it was… my imagination? Sure. If people had to consistently forward every port on their home router to play Fortnite, smash, etc. with a portable console you’d never hear the end of it. This is literally the first time I encountered someone saying this was a problem. Regardless, most people don’t buy routers— they use the ones their ISPs gave them, and I haven’t seen one of those come without upnp in at least a decade. You’re seeking out reasons to dislike NAT.