Arp-Scan

Arp-Scan is a command line utility for scanning MAC addresses that are stored in the ARP Table. By default on Raspbian the timeout for ARP table entries is 60s, you can check cat /proc/sys/net/ipv4/neigh/default/gc_stale_time for exact time.

Installation

To install Arp-Scan, from the command line enter: Note: you may have to do a sudo apt-get update first.

sudo apt-get install arp-scan

Operation

To use arp-scan enter the following from the command line:

sudo arp-scan -l

arp-scan will not show the local NIC doing the scan mac address

Example Output

Interface: eth0, datalink type: EN10MB (Ethernet)
Starting arp-scan 1.8.1 with 256 hosts (http://www.nta-monitor.com/tools/arp-scan/)
192.168.100.1 11:1d:aa:a6:66:1b DrayTek Corp.
192.168.100.2 aa:ac:6f:0c:cf:66 Dell Inc
192.168.100.3 ac:da:0b:6b:cd:ab (Unknown)
192.168.100.4 ab:61:bb:df:da:dd (Unknown)
192.168.100.5 aa:00:eb:06:ba:bd (Unknown)
192.168.100.6 aa:00:eb:a0:ba:ab (Unknown)
192.168.100.7 aa:aa:b6:6a:ba:d1 (Unknown)
192.168.100.16 b1:bd:6c:1e:b6:bb (Unknown)
192.168.100.61 11:1a:fb:bb:6b:a6 BSkyB Ltd
192.168.100.66 a6:aa:6e:b1:ba:d1 (Unknown)
192.168.100.66 a6:aa:6e:b1:ba:d1 (Unknown) (DUP: 2)
192.168.100.60 aa:ae:6a:0b:ba:a1 (Unknown)
192.168.100.62 11:ae:fa:f1:ab:aa (Unknown)
192.168.100.63 fb:6c:ba:ec:1f:ab (Unknown)
192.168.100.64 aa:ae:6a:1a:10:1d (Unknown)

*Note: these are fabricated IP and MAC Addresses so don't go looking for them :)