Hi!

If you are connecting wirelessly, make sure the built-in airport on your mac is enabled. Then proceed with the wireless settings. Please check if the wireless settings on your airport matches the wireless settings of your router like the SSID and wireless encryption. If your encryption is WEP, you need to put a "$" sign(without the qoute) before the WEP key like $1234567890. You don't need to put the $ sign if your wireless encryption is WPA. You might as well try to connect your mac wired to the router and verify if it is online. Verify that your mac doesn't use static IP address on the airport's tcp/ip, it should be on Automatic or DHCP.

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