It’s not often that you’ll need to know the MAC address of a networked device. Maybe you want to set up a MAC filter for your wireless network (which is pointless, since MAC addresses are sent in clear text, but I digress). Or maybe you want to set up QoS rules on your router. In any event, you need the MAC address for a device, but you just don’t want to walk all the way across the house to get it… or maybe the device is difficult to get to – perhaps locked away in a server room, and you don’t have a key.
All you need to do to get the remote IP address is to ping the device (Start > Run > CMD > ping [ip address]) and then run the ARP -A command at the command-prompt:
Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.
C:\Documents and Settings\jcofer>arp -a
Interface: 192.168.1.100 — 0x10003
Internet Address Physical Address Type
192.168.1.3 aa-fb-c8-34-da-7a dynamic
Windows will make a list of all the computers you have connected to recently. As you can see in the example above, my local IP address is 192.168.1.100. The only computer I’ve connected to lately was 192.168.1.3 – which has a MAC address of aa-fb-c8-34-da-7a.