Hopefully this is a quick and simple question. I need to monitor the number of MAC addresses crossing our WAN (over 254, there is an extra charge). Does anyone have a simple way to constantly monitor the number of MAC addresses going through a network? I could use some sniffer like wireshark but that would take significant time for export and searching. There must be an easier method. BTW this connection covers several subnets, so something in promisc mode just grabbing the MAC addresses it what I am looking for.