I've seen an iot app do it via multicast - the destination MAC isn't encrypted in the wifi frames, and the last one or two bytes of them are controlled by the s

I've seen an iot app do it via multicast - the destination MAC isn't encrypted in the wifi frames, and the last one or two bytes of them are controlled by the sending app. I figured this out when I tried to debug why the pairing didn't work from my phone, but did from an old Samsung A2: the iot device only had a 2.4ghz module, my new phone was on 5ghz...