Hope I'm not reviving too old a thread, but this has all the ingredients.
Same errors in Gateway log:
dpinger WAN_DHCP 67.87.80.1: sendto error: 65
General log: (starting round this time)
check_reload status updating dyndns WAN_DHCP
In the firewall log I noticed:
Block 192.168.100.1 port 67 (my modem) to port 68 192.168.100.20 (I assume this is the ISP DHCP server)
I rebooted pfsense and created a new firewall rule for the WAN interface to pass:
Source 192.168.100.1 IPv4 UDP
Destination 192.168.100.20 port 68
I just wanted to confirm if this is the correct remediation.
Edit: I spoke too soon
DHCP timed-out again and I got this in the firewall log
Oct 11 15:33:07 WAN Block ULA networks from WAN block fc00::/7 (12000) 192.168.100.1:67 192.168.100.20:68 UDP
Well, my rule was wrong (from port 68 to 68)
Changed to Source any IPv4 UDP 67, destination 192.168.100.20 68
Edit 2:
The firewall log got me looking at my WAN interface connection. I have Block Private networks checked. Perhaps this is why the WAN interface is blocking the modem from sending traffic.