yes, even if both, the server and the AdvancedHMI are off, there's still packets. I resolved the question.... I used a switch between my CPU and my PLC, the switch give my PC an internet access..
the Omron packets are between the switch and the PLC.. when I disconnect the plc from the switch and plug it in my PC, the packets stop,
but even if I bypass the switch, I cannot sniff any AdvancecHMI packets from WireShark...