Apple MacBook Pro (15-inch, Early 2011) - Manual (Page 60)

60 Chapter 4 Problem, Meet Solution
To use Network Diagnostics:
1 Choose Apple () > System Preferences.
2 Click Network and then click “Assist me.”
3 Click Diagnostics to open Network Diagnostics.
4 Follow the onscreen instructions.
If Network Diagnostics can’t resolve the problem, there may be a problem with the
Internet service provider (ISP) you are trying to connect to, with an external device you
are using to connect to your ISP, or with the server you are trying to access. You can try
the following steps.
Cable Modem, DSL Modem, and LAN Internet Connections
Make sure all modem cables are firmly plugged in, including the modem power cord,
the cable from the modem to the computer, and the cable from the modem to the wall
jack. Also check the cables and power supplies to Ethernet hubs and routers.
Turn off your DSL or cable modem for a few minutes, and then turn it back on. Some
ISPs recommend that you unplug the modem’s power cord. If your modem has a reset
button, you can press it either before or after you turn the power off and on.
Important: Instructions that refer to modems do not apply to LAN users. LAN users
might have hubs, switches, routers, or connection pods that DSL and cable modem
users do not have. LAN users should contact their network administrator rather than
an ISP.