> I have a Raspberry Pi 3 with a USB Ethernet dongle that itâ??s plugged into,$
You can use ARP for that only after it comes up far enough to get an address and speak ARP. If the Pi 3 is anything like the one I had the misfortune to deal with at work a while back, it's running a Linux with a surprising number of tools renamed, crippled, or just plain missing. But if it's got tcpdump, that's the tool I'd normally use for this: connect the NCD to the Pi (or whatever other machine) with a crossed cable (or possibly straight, if the machine's Ethernet is auto-X, or whatever else is necessary, if it's not twisted-pair). Then start tcpdump, as in tcpdump -n -s 2000 -i wm0 (or whatever the actual interface name is intead of wm0). /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML [email protected] / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
