I'm at a wifi hotspot where, when I look up the router's MAC address by two different methods, I get slightly different results:
$ arp -a
? (10.128.128.128) at 00:18:0a:58:WX:YZ [ether] on wlan0
? (10.0.2.15) at 00:18:0a:58:WX:YZ [ether] on wlan0
$ iwconfig
lo no wireless extensions.
wlan0 IEEE 802.11abgn ESSID:"PEETS"
Mode:Managed Frequency:5.765 GHz Access Point: 02:18:5A:58:WX:YZ
Bit Rate=520 Mb/s Tx-Power=22 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Power Management:on
Link Quality=42/70 Signal level=-68 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:153 Invalid misc:15 Missed beacon:0
(Last two bytes of the MAC are obscured for privacy, but they're the same in all of these cases.)
The only difference between the two is that in the one from iwconfig
, the "locally administered" bit is set to 1 (making it like a private IP address).
Why is iwconfig
showing it as a local, non-unique MAC when arp
(and /proc/net/arp
) shows a globally unique (and likely the accurate) one?
Note: In my search, I found someone else observing the same thing, in a very different (Windows) context, but no explanations:
MAC address in arp table doesn't match actual MAC, why?