Finding MAC addresses of all devices in LAN

Recently I had to find mac addresses of all servers in the local area network (LAN) for preseeding Debian installations using PXE (I will soon write about it). Finding them is easy with nmap

I used the following command and I had the mac addresses along with their associated IPs of all devices in the LAN. To find mac addresses, nmap must be run as root

nmap -sP 192.168.2.*
Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2010-03-31 12:39 EDT
Host 192.168.2.1 appears to be up.
MAC Address: 00:02:B3:40:E0:AA (Intel)
Host 192.168.2.2 appears to be up.
MAC Address: 00:02:B3:40:E0:A5 (Intel)
Host 192.168.2.3 appears to be up.
MAC Address: 00:02:B3:40:E0:A5 (Intel)
Host 192.168.2.11 appears to be up.
MAC Address: 00:1B:2F:6B:B7:AC (Unknown)
Host 192.168.2.34 appears to be up.
MAC Address: 00:1F:C6:C9:A7:54 (Unknown)
Host 192.168.2.39 appears to be up.
MAC Address: 00:17:A4:93:59:EF (Global Data Services)
Host 192.168.2.50 appears to be up.
MAC Address: 00:1E:8C:04:A5:1F (Unknown)
Host 192.168.2.57 appears to be up.
MAC Address: 00:05:5D:E0:32:DF (D-Link Systems)
Host 192.168.2.71 appears to be up.
MAC Address: 00:03:47:A9:F3:D1 (Intel)
Host 192.168.2.79 appears to be up.
MAC Address: 00:1C:C0:9D:7F:9D (Unknown)
Host 192.168.2.80 appears to be up.
MAC Address: 00:1C:C0:9D:7D:51 (Unknown)
Host 192.168.2.82 appears to be up.
MAC Address: 00:15:58:32:5C:F4 (Foxconn)
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