Forum Thread: Arp Confusion?

Hello, Null Byte friends!
As many of you know, I mostly specialize in social engineering, so things like arp requests give me a headache.

Here is my dilemma.
On two different networks when I ran the command "arp -a" on my terminal, my computer replied with:
? ( at e8:94:f6:b1:6:8c on en0 ifscope ethernet
? ( at ff:ff:ff:ff:ff:ff on en0 ifscope ethernet

One of them at the top, of course being my router, and the bottom one is probably some local loopback stuff. However, when I told my friend to run the same command, it spat out plenty of hosts and mac addresses.

Does anyone know what's going on? I can't really fix it with a google search because it doesn't provide much information for my specific case.

Here is some more information about my computer:
OS: OSX Yosemite
Type: Macbook Air
Info: Unix Based

Any help is much appreciated! Thanks!

2 Responses

Are you trying to read your arp cache? You might not have any entries, if you ping a host in your network it should appear in your arp cache as it updates. You could write a simple script to ping all IPs and then run the same command.

Thank you! Again, I had no idea what arp did. I thought it would just list me every host with their mac address (silly me). I pinged my own IP address and did arp -a again and thankfully got my response I was hoping for. :)

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