I recently wanted to add a static IP address in my router for a Network Attached Storage (NAS) on my Local Area Network (LAN). The trouble was that I could not find the MAC address for my NAS in its administrative interface.
Armed with just the IP address I found that getting the MAC address was quite easy. I opened a command prompt and typed in the following command:
arp -a 192.168.0.10
The only caveat with using this command is that a recent connection to the IP address in question must have been made by the machine issuing the command.
This is certainly quicker than downloading and installing any of the shareware available for this purpose.