We've had clients asking why their CDN is not working, it is often a PHP setting that causes the below header to be sent:

  expires: Thu, 19 Nov 1981 08:52:00 GMT
 

Solution Edit your /etc/php.ini

Set the option below as just being empty.  Generally the default is nocache and will result in sending the expires header from 1981.

session.cache_limiter =

Here is what the man says about the option:

; Set to {nocache,private,public,} to determine HTTP caching aspects
; or leave this empty to avoid sending anti-caching headers.
; http://php.net/session.cache-limiter
 

However, we have often seen that any option but being empty results in the expires header being sent.  If you want your content to be cachable by CDN, then make sure the session.cache_limiter contains a NULL/empty value.

apache, php, expires, header, cache, cdnwe, ve, cdn, thu, nov, gmt, edit, etc, ini, generally, default, nocache, cache_limiter, determine, http, caching, aspects, headers, limiter, content, cachable, contains, null,

Latest Articles