At CloudFront behaviour setting, is "All" the one to forward all request headers to the origin?
If you configure CloudFront to forward all headers to your origin for a cache behavior, CloudFront never caches the associated objects. Instead, CloudFront forwards all requests for those objects to the origin. In that configuration, the value of Minimum TTL must be 0.
Yes, it is.
The documentation seems to focus more on caching based on headers and less on what's forwarded, but caching on headers and forwarding headers to the origin go hand-in-hand.
As I was looking for clear citations from the documentation, one reference I found in the Amazon CloudFront Developer Guide is the one shown below. It's a link to a section titled "Cache Based on Selected Request Headers" but its anchor tag is DownloadDistValuesForwardHeaders.
This suggests that someone has tried to clarify or simplify the documemtation... with apparently limited success.
Note that this forwards almost all headers to the origin, except for some that are still stripped for security and/or operational reasons, like X-Forwarded-Proto, X-Real-IP, and X-Edge-*.
Note also that if your origin protocol is HTTPS and you were not already whitelisting the Host header at CloudFront, then whitelisting all headers will potentially change the requirements for the origin's TLS certificate. Failure to handle this correctly is one of several reasons why CloudFront might return a 502 error to the viewer.
