Mac OS X 10.6: Using Network Diagnostics
You can use Network Diagnostics to help solve Internet connection problems. If you can’t connect to the Internet, Network Diagnostics opens and walks you through solving the problem.
You can use Network Diagnostics to diagnose problems related to your Ethernet, AirPort, or internal or external modem connections. If you are trying to connect to the Internet using another method, see the documentation that came with your Internet account.
If Network Diagnostics can’t resolve the problem, there may be problems 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.
If your Internet connection is working properly, but you are trying to connect to the Internet using a different network port configuration, use Network Diagnostics to investigate your network settings.
To use Network Diagnostics:
Choose Apple menu > System Preferences, and then click “Assist me.”
Click Diagnostics to open Network Diagnostics, and then follow the onscreen instructions.
To set up a new network port configuration, you can click “Assist me” in the Network pane of System Preferences, and then click Assistant. Network Setup Assistant opens and helps you configure a new network port.