> What really surprises me WHY they send this header at all ?

You would assume that a CDN would clean/normalize the requests to the backend, and not use the Q qualifiers at all. But maybe in some cases they just pass the accept-encoding header which they receive from the client.

In this case I tracked it down as a large corporation behind a Microsoft ISA firewall, which could not access our css/js. They were accessing the cdn with the origin being our nginx servers. I can't comment on the choices that microsoft firewalls make in their request headers ( or the companies that use them, or how they configure them ), but it appears that they do follow the RFC in this case.

In order to guarantee correct delivery via nginx, is the only workaround right now to disable compression on all our css/js content? Or can you think of something else?

Thanks Igor.

Let me know if there is anything I can do to help.

Radek Burkat
www.pinkbike.com