External Max-Age

Category: Caching

Purpose: Determines the max-age interval for browser to edge server cache revalidation. In other words, the amount of time that will pass before a browser can check for a new version of an asset from an edge server.

Enabling this feature will generate Cache-Control:max-age and Expires headers from our edge servers and send them to the HTTP client. By default, these headers will overwrite those created by the origin server. However, the Cache-Control Header Treatment and the Expires Header Treatment features may be used to alter this behavior.

Key information:

This action does not affect edge server to origin server cache revalidations. These types of revalidations are determined by the Cache-Control/Expires headers received from the origin server, and can be customized with the Default Internal Max-Age and the Force Internal Max-Age features.
Configure this feature by specifying an integer value and then selecting the desired time unit (i.e., seconds, minutes, hours, etc.). This value defines the external max-age interval that will be applied.
Setting this feature to a negative value causes our edge servers to send a Cache-Control:no-cache and an Expires time that is set in the past with each response to the browser. Although an HTTP client will not cache the response, this setting will not affect our edge servers' ability to cache the response from the origin server.

Default Behavior: The Cache-Control/Expires headers cached with the response of the origin server will pass through to the browser.