Local subnet multicast rules



  • I have three bridges on my pfSense, with the firewall rules being enacted on the bridges instead of their member interfaces. This works great. There's multicast traffic on the interfaces, though, and I want to make sure that the router will allow local-subnet multicasts on the interface but not between interfaces. This is based on Wikipedia's description of multicast (https://en.wikipedia.org/wiki/Multicast_address):

    Addresses in the range of 224.0.0.0 to 224.0.0.255 are individually assigned by IANA and designated for multicasting on the local subnetwork only…Routers must not forward these messages outside the subnet in which they originate.

    Do I need to create explicit rules to enforce this on each bridge interface? Maybe a pair of rules like:

    • pass any from "Bridge1 net" to 224.0.0.0/24

    • block any from * to 224.0.0.0/24