OS X Mountain Lion: Choose preferred Wi-Fi networks
By default, your Wi-Fi connection attempts to join the wireless network your computer was most recently connected to.
If you are in an environment with more than one wireless network, you can set up your computer to join a preferred network when you start your computer, wake it from sleep, or turn Wi-Fi on.
OS X keeps track of the wireless networks your computer has connected to, and lists them in the Wi-Fi pane of Network preferences.
- Choose Apple menu > System Preferences, and then click Network.
- Choose Wi-Fi in the network connection services list, and then click Advanced.
If Wi-Fi isn’t in the list, make sure you have an AirPort Card in your computer, and then click Add (+) at the bottom of the list. Choose Wi-Fi from the Interface pop-up menu, give the service a name, and then click Create.
- Click Wi-Fi. If the networks you expect to see aren’t in the preferred networks list, click Add (+) at the bottom of the list, and then choose the network you want. Enter the network password if necessary.
To give a network the highest priority, drag the name of the network to the top of the list. This is the network your computer will attempt to join first.
Select a network and click Delete (-) to remove it from the list.
Use the checkboxes to set other advanced Wi-Fi options.