Go to the Apple menu and select System Preferences.
Under Internet and Network, select Network.
- Change the Show pop-up option to Built-in Ethernet.
- For Location, choose Automatic (or give this connection a name)
- For Show, Select Built-in Ethernet
- Select the TCP/IP tab
Set Configure to Using DHCP (an IP address starting with 131.215. should appear).
- Click the Apply Now button, then quit the System Preferences application.