[neon5077]

Nope! Only WiFi and Ethernet. I had been using my phone hotspot, but that gives me a sane IP in the local reserved block, not one from the public block.

I also was using our neighboring business's guest WiFi, but again that should have given me a sane local IP.

Every diagnostic I could think of told me I was directly connected to the WAN with no intervening networks. Then again I'm not the best at debugging networks so I could be mistaken on this point. I am 100% certain that the IP address my computer was given was not a legal local network address.

[hunter2_]

Very interesting! Some kind of buggy DMZ type of thing, perhaps, where even the DHCP traffic flowed right on through... who knows.

[neon5077]

That's about the only thing that makes any sense. Maybe it somehow faulted to route all traffic straight to the ONT, which could only give one address which I happened to get. And then the fiber got cut the very next day around the same time as we got the new router.

A lot of coincidences and extraordinary edge cases, but it's plausible I guess?