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Troubleshooting Wi-Fi issues in OS X Lion and Mac OS X v10.6
Symptom: My Mac does not connect to the Internet
- Webpages do not open in Safari or other web browsers. These pages may be blank or you may receive an alert that "You are not connected to the Internet".
- Internet applications such as Mail, iChat, or the App Store cannot connect to their servers.
Note: Routers may be configured to allow some services to use the Internet (such as Mail) while preventing other services from using the Internet (such as web browsers). If you are not sure whether your network is configured in this manner or not, contact your network administrator. If your network is not configured in this manner and some Internet applications work, but others do not, then the issue is probably not related to your Wi-Fi network.
Hope this helps,