We discover an interesting issue using ESXi 4.1 and Beacon Probing :
In ESXi 4.1 (I don't remember if it was the same in 4.0), default Management Network (vmk0) uses the mac address of the physical nic identified as vmnic0 and spoofs it on another interface if vmnic0 become unavailable..
On a vSwitch0 (with 3 physical nics minimum), if you configure Beacon Probing, your ESXi will transmit packets originating from each physical nic mac address.
So, if your default Management Network move to another interface than vmnic0 with Beacon Probing enabled (using standby mode or after a failover), two physical ports will use the same mac address and you will experience packet loss to the Management Network and perhaps HA Failover.
Has someone else notice this problem ?
Could you verify mac adress used by vmk0 on your ESXi other that 4.1 ?
On ESX there's no problem as the mac address of the service console is a vmware virtual mac address.
