I've got a machine behind a firewall (fortigate) that is only supposed to access a certain url, so, we whitelisted that url on the firewall and also the google dns servers: Every other traffic is forbidden. The problem is that said page has some css styles that call the google api for fonts: fonts.gstatic.com and fonts.googleapis.com (as far as I can tell)
For the life of me, I always get timed out on the fonts when accessing the web page, even though I added the FQDN as permitted traffic.
Am I missing any other url or anything you could come up with? I'm out of ideas.