Find Out MAC Addresses, the Easy Way

When securing a (wireless) Windows network, in addition to using security protocols such as WEP (Wired Equivalent Privacy) or WPA (Wi-Fi Protected Access) encryption, you can use Media Access Control (MAC) address filtering.
When MAC address filtering is enabled, the access point, router or firewall software verifies that the network card in the computer requesting access has a MAC address in its filter list before allowing or denying the computer to access the network. This means that you must first obtain the MAC addresses of each computer in that network in order to build that access list. To do so you don't ave to manually visit each computer and use the getmac or ipconfig /all commands. An easier way to gather MAC addresses is to take advantage of the ARP (Address Resolution Protocol) command. First, use the ping command to ping the computer you want to find out its MAC, then run (in a command prompt window) the command "arp –a" (without the quotes of course).
When used with the –a parameter, the ARP command displays the ARP cache, which stores the IP and MAC addresses of the computers that most recently accessed the system, or in this case, those computers that responded to the ping command.