By default, IIS7 has built in support for various webfont MIME types so you might not notice any problems at first.. but once you try to serve these files over a CDN such as Akamai or CloudFront (like I was) you’ll quickly notice that your web fonts do not load properly in IE or FireFox. The reason is that these browsers (and maybe others) follow the Cross Origin Resource Sharing spec that prevents a page hosted on one domain from accessing resources hosted on another domain.
In other words, if your page is hosted at http://www.mydomain.com and your CDN provides a hostname such as http://mycdn.somecdnprovider.com, there is a good chance that you will not be able to access your web fonts correctly.
The solution is easy: Add a header to your resources that informs the browser of allowed domains using the Access-Control-Allow-Origin header.
If you are hosting an ASP.NET application in IIS7+ you can easily add this header by modifying your web.config file as follows:
You’ll also need to have the URL Rewrite module installed.