dhcpcd-discuss

On 6/15/20 4:15 AM, Stuart Henderson wrote:
> On 2020/06/13 17:30, Bruce Ferrell wrote:
> > I'm in the process of tracking down the MAC address of all the android
> > devices... Like my Amazon smart plugs.� They don't to respond to pings so
> > it's an interesting issue to track down.
> btw, for this you might like the program called "arp-scan".
Hi Stuart,

Thanks for the pointer.

I was looking for something like this when I started trouble shooting the issue.

I found some commercial tools and walked right past them.

Then I realized I could do tcpdump on my AP and watch the wifi interface for  the traffic... first point I could monitor.

The AP know what MAC addresses are connected so I used a command like this:


tcpdump -nni ath1 ether host <MAC ADDRESS>


As the AP is not configured to be a router, it simply bridges the wifi traffic onto the LAN and I can pick out each connected device by monitoring the wifi interface. That's how I 
identified the IP addresses used by each device... I "used" a each device and watched for traffic.

Even if it doesn't respond to ICMP, when it starts talking, I can see it's IP address and I know which device I was using.