Add another layer of validation for the cached objects. Validation of entity tags improves efficiency of caches and saves bandwidth by preventing unnecessary data transfer.

How it works

Instructs edge servers to compare the request's If-None-Match header with the ETag value of the cached object. If they are the same, the edge server returns a 304 Not Modified response containing only headers. If they differ, the edge server requests a new copy of the object from your origin server. This validation occurs in addition to the default validation of Last-Modified and If-Modified-Since headers.

You can specify whether this behavior should support only strong ETag values, ignoring weak ETag and always returning a full response, or weak values should also be accepted. For more details, see the RFC Standard.

Features and options

Field	What it does
Enable	Enables the ETag validation.
Allow non-strict Strong ETags	Whether you want to allow Strong ETag values that are not surrounded by double-quotes - technically these are malformed and non-standard, but are commonly used.
Support Weak ETags	Whether you want to allow Weak ETags that start with "W/".