My favorite program for this is fing from overlooksoft.com 
(http://www.overlooksoft.com/).  They have recently updated their web 
site to stress their phone app, but they do have a linux rpm (under 
their "Fing for Desktop") that works well.  It finds all of the mac 
addresses on a network, and looks them up to return their names and IP 
addresses also.

Paul

On 07/27/2014 01:36 AM, ToddAndMargo wrote:
> Hi All,
>
> I have been Duck Duck Go'ing looking for how to discover
> all the mac addresses on my Ethernet.
>
> http://www.linuxinternetworks.com/how-to-find-out-all-mac-address-on-network/ 
>
>
> Says to do:  nmap -sP 192.168.1.0-255
>
> Done that before and it does give you all the mac addresses
> on 192.168.1.0/24, but it does not give you mac addresses
> for those devices with different network configuration
> on your Ethernet.  (Like a stray access point on
> 192.168.88.0/24 on your Ethernet.)
>
> I have tried these guys' java script:
> http://www.ubnt.com/downloads/discovery/ubnt-discovery-v2.3.zip
> It runs but doesn't find anything.   Ran it in an XP VM too
> and it struck out there either.
>
> Does anyone know how to get all the mac addresses on your
> Ethernet, even the ones configured on another network?
>
> Many thanks,
> -T