Any changes you've made will automatically be saved. If you connect to the Internet through a proxy, compare Firefox's settings to another browser's (such as Internet Explorer - see Microsoft's guide to proxy settings) (such as Safari - depending on your OS X version, see Mac OS X 10.6: Enter proxy server settings, OS X Lion: Enter proxy server settings, or OS X Mountain Lion: Enter proxy server settings).

If you don't connect to the Internet through a proxy (or don't know whether you connect through a proxy), select No Proxy.In the Network Settings section, click Settings….In the General panel, go down to the Network Settings section.Click the menu button and select Settings. In the Menu bar at the top of the screen, click Firefox and select Preferences.To check your connection settings in Firefox: If you connect to the Internet through a proxy server that is having connection problems, you will not be able to load websites. For instructions on how to configure some programs, see the Configure firewalls so that Firefox can access the Internet article. In general, you should make sure your Internet security software is up-to-date and remove Firefox from your program's list of trusted or recognized programs, then add it back. Note: Some Internet security programs can block Internet access even when they are in a 'disabled' state.

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