On 2014-07-27 08:36, 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

MAC is layer2 so you cannot get the MAC from a different subnet, however you can detect smb enabled system with the following command

$ sudo nmap -sU --script nbstat -p137 $subnet
$ nmap -sn --script address-info $local_subnet

or with http://www.inetcat.net/software/nbtscan.html
$ nbtscan $subnet

To get all MAC addresses use the network equipment

Example for cisco:
# sh mac address-table
# sh ip arp


For long time monitoring / reporting use netdisco, nedi or other tools.