Extending Craig's answer for latest bootstrap that includes WOFF2 files. You can also add in
<system.webServer> <staticContent> <remove fileExtension=".woff2" /> <mimeMap fileExtension=".woff2" mimeType="font/woff2" /> </staticContent> </system.webServer> (See Proper MIME type for .woff2 fontsProper MIME type for .woff2 fonts for a discussion on current mime type for WOFF2 files)