[MarkL]

"I don't want to get in too deep - but, despite NAT/DHCP, every single computer has a NIC which has a MAC address. The sender at Reuters IP address must have sent a packet/frame with a MAC Sender ID and a MAC recipient ID (or a numerical derivation of said address)."

Sorry to burst your bubble, but that's just not going to work. First off, you can change the MAC address using software that's probably on your computer right now (within the network drivers). But you won't need to: You see, if there's a bridge or router between the source and destination, then the source MAC address is gone, and the destination MAC address no longer matters. Wiped away. The IP protocol couldn't care less about the MAC address. In fact, even if it knew what it was, it wouldn't know what to do with it. The MAC address is only useful in identifing a network interface on a local network.

Mark

[backhoe]

Sorry to burst your bubble, but that's just not going to work. First off, you can change the MAC address using software that's probably on your computer right now (within the network drivers). But you won't need to: You see, if there's a bridge or router between the source and destination, then the source MAC address is gone, and the destination MAC address no longer matters. Wiped away. The IP protocol couldn't care less about the MAC address. In fact, even if it knew what it was, it wouldn't know what to do with it. The MAC address is only useful in identifing a network interface on a local network.

I did not write that, but I appreciate the further info.