Edit: I did some research on the Google Fiber reddit and it seems like broken port forwarding is a common issue with the provided hardware. Most say just BYO router. Sigh.
Tl;Dr: port forwarding isn't working after a network hardware upgrade, even after enabling it and rebooting all equipment, and without a firewall enabled.
I've been running a public-facing Jellyfin server on Ubuntu 22.04 for the past few months without too much trouble. Today I upgraded my networking equipment to a Google Fiber Network Box. I ended up having to set a new static IP address for my server device. I also had to switch from using the Google Home app to using the Google Fiber app or website to configure my network. Everything's working now except for port forwarding. The network settings give me the ability to forward ports, but port checkers keep telling me the ports I've opened are not open.
I've tried rebooting the server, router, and modem (and closing and reopening the ports) multiple times to no avail. UFW is installed on the server but it's inactive, and I don't have any other firewalls. I don't know what else could be blocking the ports.
I'm still sort of a newbie to self hosting, so maybe there's something I'm overlooking. But I've done several web searches and couldn't find any solutions I haven't already tried.
I did notice though that it seems every device on the network has the same public IP address. I don't know for certain that wasn't the case with my old setup, but it did seem strange. Again I'm not an expert on this stuff, so maybe it's nothing. I couldn't find anything in network settings that would let me change that either.