Surrogate-Control
Alternative to Cache-Control response header for CDNs and reverse proxies.
Fastly reads this header from responses. It is proprietary to Fastly.
Fastly processes Surrogate-Control in a similar way to Cache-Control in order to determine the initial TTL (freshness) of a resource, but will prefer Surrogate-Control over Cache-Control if both exist.
HINT: If you are using service chaining, the Surrogate-Control header is passed to all services in the chain. If, for example, you do not want the "first" service (the service receiving public traffic) caching responses, you must unset or overwrite Surrogate-Control.
Example
Cache-Control: max-age=0Surrogate-Control: max-age=86400, stale-while-revalidate=60