How does a firewall/vwire handle ethercode 0x0721

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How does a firewall/vwire handle ethercode 0x0721

L1 Bithead



we are currently setting up a clean pipe for Cisco ACI setup, so the intra-ACI traffic will pass the vwire, to have basic IPS inspection done.

Our setup is an A/P HA with a vwire.

Cisco is using Layer-2 ping with ethercode 0x721 to check, if the path is free or blocked.


We have some issues with failovering and we doubted, that the L2-Pings are even sent out, because with packet-capture we cannot see anything. Also there was the case, that ACI saw both peers as up, but the passive firewall shouldn't pass any traffic on the vwire.


Does anyone of you got ideas regarding that? Maybe special config is necessary, to have this packets pass? I'm only aware of zone-protection settings, where we can exlude inspection for certain ethercodes, but ZP is not active on the vwire zones - also no counters are seen there.


Looking forward to any input


Best Regards


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