@jeff3820 said in So why is my firewall logs full of mDNS pings that should pass??:
Still looking for the sources...
You most likely will need to sniff and see the mac address of the sender, then you should be able to at least get a clue to who it is by the maker via the first 3 of the mac, if its wired you can track that down to what port its plugged into. Wireless can block the mac and see who screams or what device stops working.
You could do the same on pfsense, once you know the mac you can see what actual IP it has and that can be helpful, maybe it registered a name with dhcp, etc.