Even "bulletproof" @font-face not working in IE9 (wordpress site on Apache)

I had the same problem, and I confirmed that it was the IE security zone settings. Some enterprises have group policies that disable font download for certain IE security zones.

The 4 typical zones are:

1. Intranet zone – sites on your local network.
2. Trusted Sites zone – sites that have been added to your trusted sites.
3. Internet zone – sites that are on the Internet.
4. Restricted Sites zone – sites that have been specifically added to your restricted sites.

To check the zone your page is on in IE9, right click on the page, then select properties. You should see a row with the "Zone" information.

The solutions:

1. Read up on your enterprise IE's Security Zones or talk to the group that manages your browser settings.
   1. Submit request to add your site into the intranet or trusted zones, if those are the ones that allow font download.
   2. Some policies just need you to use certain domain naming conventions to be in the Intranet zone.
2. Manually change IE settings for your box to allow you to develop and test things.
   1. If you have access, IE > Internet Options > Security Tabs > add specific sites to a zone that allows font download.
   2. If the Security tab is blocked, get temporary admin access, open "gpedit.msc", then drill down to Computer Configuration > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page > double click "Site to Zone Assignment list" > enable it, and add your domain name in the "Value name" column and the security zone number in the "value" column. The zone numbers are listed above respectively (e.g. 1 for Intranet zone)