packet sniffer, part of the SYGNAL broadcast toolkit, lists every device it hears on a network port: what each box is, its addresses, how to reach it from this Mac, and what it is doing (Dante, OMNEO, PTP clocks, multicast streams).

This installs a menu bar app and a capture helper (the access_bpf group), so listening needs no password.

packet sniffer doesn't start at login unless you turn on Start at login in SYGNAL toolbox.

Making a port silent or giving this Mac an address still asks for your password.