Raw Ethernet on Linux, through a packet socket (AF_PACKET) that OTP's :socket opens: frames of
EtherType 0x88A4 only, on one interface, and none this machine sent.
A packet socket needs the capability CAP_NET_RAW: root, or a BEAM given it, as with
sudo setcap cap_net_raw+ep path/to/beam.smp.
Options of open/1:
interface:, required, as"eth1"