There may be certain times you need to find the MAC Address (Physical Address) of your computer's network connections. This information may be used by an IT professional to connect you to a network, or during trouble shooting. Below are instructions for finding your MAC Address in OS X. Remember you have a MAC Address for EACH network connection (ex: one for your Airport and one for your Ethernet card)
Click the Apple, then click System Preferences.
Click Network.
Click the desired network device on the left.
Ex: Ethernet
Click Advanced.
Click Hardware.
Now you'll see the sequence of numbers for the line MAC Address. This is what you'll need.