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Comment by yamaneko | Hacker News Reader

> (I use this as pre-doorbell warning sometimes, waiting for my parents or girlfriend to connect when nearby)

That's such a great idea! Could you give more details of how are you doing that? Which tools did you use?

I turn my phone's hotspot on with the desired settings and run the following in bash (it runs Debian stuff in userspace using ru.meefik.linuxdeploy)

    tcpdump -i wlan0 -c 1 arp; aplay isd/media/0/*.mp3

This waits on the wifi interface for one ARP packet, which will surely come when a new device connects, and then plays some mp3 that's on my internal sdcard (hence the mountpoint "isd").

Not OP, but I have a cron job on a Raspberry Pi running every minute checking for known MACs with `arp-scan`. I then get an audible warning.

Would you mind posting a link to this utility? Sounds like an awesome tool!

+1 ... can we get a github repository on this.

Similar here (OP here), just without the dedicated hardware.

Does the fact that iOS randomly changes the MAC address while scanning for networks affects this in any way?

No - `arp-scan` only works if someone is associated with your AP. If I was using `airmon-ng` or similar, then yes, iOS MAC randomization would affect performance. Although, once the phone connects to the AP, `airmon-ng` may still work.

Thanks for clarifying!

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