Comment by snuxoll

NAT-PMP, UPnP, PCP, et. all primarily exist because consumer networks that have to share a public IP face more issues than simply opening a port up to the internet. Destination port conflicts, port remapping, discovery of your public IP, are huge fucking headaches that these protocols also assist with.

Given most consumer routers these days can be configured with a mobile app, I could easily foresee a saner alternative where devices could simply ask the gateway if they could open up a port and have a notification sent to a mobile app to allow it.

But, that said, given how many devices are mobile these days I think the benefit of endpoint firewalls shouldn’t be underplayed either.