Most of the Apple Machine came with few network interface. For example: Airport, Ethernet, FireWire, Bluetooth and etc.
By default, all the services are active when you turn on your Apple Machine. In Mac OS X, we can manually make the network interface become inactive.
To make the services inactive, below are steps:
- Select the network interface from the Network Service list (System Preferences->Network)
- After you select the network interface, Click the gear icon at the bottom of the list.

- Choose the Make Service Inactive from the pop-up menu
Now the network interface that you select just had became inactive. This inactive Service will never activate even the interface has connected and configured properly. For your information, this is the only way to inactivating or deleting a network service in Mac OS X.
Just try it..:-)