How to remove "Client-Peer" (etc) header in nginx with php-fastcgi
Solution 1:
Those headers were not present in the HTTP response at all. Neither nginx nor php-fpm ever sent them, so trying to block them is pointless.
They are synthetic response headers added to the response by your user agent, libwww-perl.
If you don't wish to see them, make HTTP requests with some other library, such as libcurl.