Headers added by CDN77
In order for the CDN to cache and deliver your files effectively, it adds several headers to your files when completing an HTTP response and request.
- Via: This particular header is added when the CDN requests a file from your Origin server. It is quite useful if you need to identify exactly which requests are being made by the CDN to your Origin server.
An example of what the full header looks like with the string is "Via: cdn77" or "Via 1.1 cdn77". For instance, if you are filtering this information out from your logs, it functions as an identifier.
- X-Forwarded-For: This is the IP Address from the TCP connection from which our CDN Edge server received the request. For example, if the IP address which is received from the TCP connection is 22.214.171.124, the full header would be X-Forwarded-For: 126.96.36.199
- X-Edge-IP: This header gives you the IP address of the CDN77 Edge server, which completed the HTTP response and delivered the file.
- X-Edge-Location: This header is used to identify the geographical location of the CDN Edge that delivered your file. (City, Country)
- X-Age: This header gives you information about how long your file was kept in the CDN77 cache in seconds. It is only added if the header X-Cache results in a cache HIT.
- X-Cache: The entry of this header determines the following:
HIT – The response was cached and correctly delivered by the CDN.
MISS – The response was not cached by the CDN and therefore was fetched from an origin server.
BYPASS – The response was fetched from the origin server instead of served from the cache because the request matched a proxy_cache_bypass directive.
EXPIRED – The entry in the cache has expired. The response contains fresh content from the origin server.
STALE – The content is stale because the origin server is not responding correctly, and proxy_cache_use_stale was configured.
UPDATING – The content is stale because the entry is currently being updated in response to a previous request, and proxy_cache_use_stale updating is configured.
REVALIDATED – The proxy_cache_revalidate directive was enabled, and NGINX verified that the currently cached content was still valid.