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ip-addressmac-address

arp command - what does it all mean? *and* getting a wireless router MAC address from IP

When I type in arp -a in my bash shell, I get output that looks like the following:

? (10.0.0.1) at 0:f0:7f:43:e8:68 on en1 ifscope [ethernet]
box1.google.com (10.0.0.3) at 0:1f:fe:fe:ca:d4 on en1 ifscope [ethernet]
box2.google.com (10.0.0.2) at 0:2:a3:45:90:bf on en1 ifscope [ethernet]
box3.google.com (10.0.0.50) at 78:e7:df:7c:34:c on en1 ifscope [ethernet]
box4.google.com (10.0.0.230) at 0:80:74:c9:50:d5 on en1 ifscope [ethernet]
box5.google.com (10.0.0.256) at 0:23:df:91:4f:9e on en1 ifscope [ethernet]
box6.google.com (10.0.0.458) at 0:15:9:89:36:68 on en1 ifscope [ethernet]
? (10.0.0.179) at 0:2a:32:f0:f4:d0 on en1 ifscope [ethernet]
box7.google.com (10.0.0.283) at 0:27:16:66:2d:ef on en1 ifscope [ethernet]
box8.google.com (10.0.0.386) at 0:13:eb:91:d8:b5 on en1 ifscope [ethernet]
box9.google.com (10.0.0.287) at 0:1c:25:10:d8:89 on en1 ifscope [ethernet]
? (10.0.0.255) at (incomplete) on en1 ifscope [ethernet]
? (172.17.122.255) at (incomplete) on vmnet8 ifscope [ethernet]
? (172.17.254.1) at 0:50:56:c0:0:1 on vmnet1 ifscope permanent [ethernet]
? (172.17.254.255) at (incomplete) on vmnet1 ifscope [ethernet]

What does all of this mean? I loosely understand that I'm seeing domain names, IP addresses (internal IP addresses?), and MAC addresses. How do I find the MAC address for the wireless router that I'm connected to? Why are there so many entries here? I figured that there would only be one for my computer, one for the wireless router, one for the cable modem, and then possibly some other things upstream... but I'm seeing other computers that are not mine. Furthermore, I am not seeing my computer. Also, could I somehow use information like this to find the MAC addresses for wireless routers in public? What if I can not connect to said public routers?

Solution

  • At a guess 10.0.0.1 looks like the gateway. Why do you want to find the MAC address for the router you are on? Also, if you cannot connect to a wireless router then you won't be able to find it with this command, there are some other commands you can use to scan for wireless signals. You don't see your computer on there because this is your local arp table, why would you need to know where you are? You're already there.