Bridged VLAN not passing parent MAC in ARP response



  • Hello,

    Thank you for this incredible software package. I use it constantly and appreciate all the hard work that goes into it. I've spent enough time searching these forums to know that questions related to bridging often elicit frustrated responses. Questions related to VLANs and bridging at the same time garner even more frustrated responses. So it is with great hesitation I explain my issue.

    I have a VLAN interface bridged...
    The parent bridge is assigned an IP address and a MAC address.
    The VLAN interface has no configured IP, the MAC section is grayed out, stating "The MAC address of a VLAN interface must be set on its parent interface"
    Related system tunables have been set
    net.link.bridge.pfil_member to 0.
    net.link.bridge.pfil_bridge to 1.

    When I boot up a host in this bridge, it gets an IP address, ARPs for the gateway and the gateway responds with the bridge MAC address. No further uni-cast traffic makes it to the bridge or VLAN interface according packet captures.

    If I change the bridge address (dangerously?) to the VLAN member's parent (duplicate) mac, all traffic starts flowing. No firewall issues. It seems like a L2 MAC / ARP issue.

    It seems that the MAC address of the VLAN interface is what is needed to for host communications to flow, but the bridge interface MAC address gets stored in the host's ARP cache and doesn't work.

    Any ideas on how to get this to work without a duplicate MAC? I'm sure there is a simple network concept that I'm not aware of that can resolve this (please don't say "buy a switch", although I'm sure it will be comment 1).

    Any help appreciated!



  • After thinking about how MAC addresses work on a switch, I replicated the MAC across all bridge members and the bridge itself, and things began working!


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