Here are things that you should be checking if your fontawesome is not working when you put your website on IIS.

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Check 1: Check if all the fonts (.otf, .woff etc) are copied to the /font-awesome-4.2.0/fonts/ folder.

Check 2: Remove the fontawesome.css from your bundle and add it directly like <link href="~/Content/font-awesome-4.2.0/css/font-awesome.css" rel='stylesheet' type='text/css' />