标题中的双缓存控制行

Question

I have set the next line in nginx:

add_header Cache-Control "max-age=259200, public";

but headers from my response look like:

Cache-Control:max-age=259200, public
Cache-Control:no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Connection:keep-alive
Content-Encoding:gzip
Content-Type:text/html
Date:Wed, 24 Sep 2014 10:21:32 GMT
Expires:Thu, 19 Nov 1981 08:52:00 GMT
Pragma:no-cache
Server:nginx/1.1.19
Transfer-Encoding:chunked
X-Powered-By:PHP/5.3.10-1ubuntu3

I have checked and I don't send other headers from server side script (PHP). How can I solve this problem...?

Update: I have discovered that this is only at PHP-generated responses...

Answer 1

I solved this problem adding the next line session_cache_limiter(false); before session_start();.