mDNS blocked on WAN - Only when Avahi package is enabled

[jim82]

Hi all,

Every 5 minutes on the dot, I see multiple entries like the ones below being blocked by my firewall.

So far I've tried and concluded the following:

• Disabling Avahi package removes the errors, but also remove my option to use Chromecast across VLAN's.
• I've been through my entire setup, to make sure there's no leaks from my internal VLAN's towards WAN. I can't seem to find any issues. My switch is only L2, so routing is done by pfSense itself.
• mDNS should not exist on WAN at all, however I'm in doubt if my Sagemcom cable modem could be the culprit in some weird way.
• Packet capture below, doesn't make me much wiser, but hoping someone can point me towards a solution.
  WAN - Promiscuous - 224.0.0.251 - Full detail:
  PCAP_WAN_mDNS.txt
  PCAP_WAN_mDNS.cap

EDIT: Source MAC address is my cablemodem in Bridge mode (40:62:31:0b:a7:d9)

I have the following devices on my network:
Sonos
Synology
Chromecast
iOS devices
Chromebooks
Windows 10 PC's

Thanks for any replies, that can help me figure out this error.

BR,
Jim