Multicast-to-Broadcast bridging (LAN<–>WLAN)

  • Hi

    General problem:
    We are using Profinet, a realtime ethernet network used in automation.
    The protocol relies heavily on multicast ethernet frames.
    We use a Wlan profinet device and pfsense as LAN<–>WLAN bridge. The profinet-wlan-device is not capable of receiving multicast frames. The PFsense bridge has to modify the multicast frames into broadcast frames.

    Partial solution:
    We have a small c-program on the bridge, using bpf, capturing all the profinet frames on the lan interface, modify the dst mac to broadcast, send them on the wlan interface. The problem with this solution is, that the broadcast frames leak to the lan side as well, where they disturb the fine siemens simatic controler.

    Is there any way to remove/filter these frames? Is there a better way to make the multicast-> broadcast conversion?

    Since ipfw is capable of layer2 filter we thought this might be an approach.
    However it seems the bpf interface inserts the frame below the firewall stack.

  • It seems that in the pfsense forum only network noobs hang around ;) not any creative idea for this problem ?

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