WAN interface DNS to Verizon servers

[JMini]

I'm on Verizon FiOS and have my OPNSense FW connected to the ONT. My WAN interface is configured to get its address via DHCP. So I'm assuming that it's getting DNS servers assigned.
I'm seeing packets leaving the WAN interface to Verizon DNS servers. Only a few. No inbound traffic from a LAN trying to go to a Verizon DNS server. Just out of the WAN interface.
I have AdguardHome set up for all internal DNS needs over DOH.

Is there somewhere that OPNSense might be using Verizon's assigned DNS servers?

[spetrillo]

The only place would be in System/Settings/General. Here you can define what DNS servers to use, but more importantly for you is if Allow DNS server list to be overridden by DHCP/PPP on WAN is checked or unchecked. If checked then your FIOS DNS servers will be used.