I use Apache as the backend proxy server to process the php files for Wordpress. If there are any headers identified in .htaccess files, such as the one in the cache directory for WP Super Cache, those headers, such as Cache-Control are sent back to the browser, along with any headers set in the http nginx.conf.
When I read about proxy_ignore_headers I thought it meant Nginx would ignore headers from the proxy server, for example headers coming from Apache in this case. Do I have that backwards?