Hi
Welcome to Apple Discussions
Wondering if you have a network proxy affecting your internet connection? To check, go to your System Preferences>Network panel. Click on the Show drop down menu and select "network port configuration". Only Airport ought to be checked (move it to the top of the list, if necessary).
Same menu, select Airport. Click on the Proxy panel. Anything selected there other than the Passive setting? If so, and you're not using a proxy service, uncheck it, select "apply", then restart Safari.
Post back