Best way to redirect non-CloudFront requests to CloudFront

[Alexandr Gomoliako]

> A summary of what I want to do is to redirect requests for image URL's
> that don't come from Amazon's CloudFront service to CloudFront. This is
...
> but this isn't possible (as remote_addr is an IP that may change) and is
> probably inefficient. Is there a correct way to redirect everything to a
> hostname that doesn't come from the hostname itself efficiently?

Check its user agent instead.