Set when a cookie header is stripped because it is too large.
Fastly writes this header into requests. It is proprietary to Fastly.
When an inbound
Cookie header attached to a request exceeds the maximum allowed length, it will be removed and
req.http.Cookie will be empty. The header
Fastly-Cookie-Overflow will be set to
"1" to allow this to be distinguished from a request that had no
Cookie header in the first place.
Fastly-Cookie-Overflow header is automatically removed from requests when they arrive on a Fastly server, before being set if the
Cookie header is too long. Therefore, in services that are configured to use clustering, the header is present only in
vcl_deliver, and will not be present in requests made to backends.