An ISP tech came out here but he of course had no idea what the problem was… verified the WAN worked with a TPlink router set to the static IP.
I'm going crazy trying to figure out what is wrong. I reinstalled pfsense, my last attempt the WAN connection worked for about a minute after turning off the modem, setting the IP to static on pfsense, then plugging the modem in.
Currently spoofing the MAC of a Cisco router. On a machine on the LAN I had a continuous ping of 8.8.8.8 running. I ran a packet capture on the pfSense WAN interface during this whole process until I lost connectivity. I saw TCP application data, DNS response, ping replies, NTP exchanges, ARP broadcasts and replies, etc. Everything working fine. 40s into the capture it stops behaving and it shows nothing but DNS queries, ARP broadcasts from the ISP Router, ping requests, some TCP retransmissions...
Right before I stopped getting ping responses for the gateway it ARPed for the static ip 5 times, once every ~30ms. pfsense responded immediately to each arp with the spoofed MAC as it did earlier in the capture. For the next 2 seconds I got 2 ping replies and then nothing. :'( :'(