thanks for responding here.
the 206 code was advised by every tutorial i found online.
i am using nginx 1.7.2, so cannot upgrade.

>You shouldn't try to add Accept-Ranges header manually. It will
>be added automatically when nginx supports range requests to the
>resource in question.

how do i notify nginx to serve particular file extensions with the accept-ranges header?

what would cause these headers to not be outputted in this case?