The ngx_http_headers_module module allows adding the “Expires” and “Cache-Control” header fields, and arbitrary fields, to a response header. expires 24h; expires modified +24h; expires @24h; expires 0; expires -1; expires epoch; expires $expires; add_header Cache-Control private;
![Module ngx_http_headers_module](https://cdn-ak-scissors.b.st-hatena.com/image/square/d623c1882630da83f7f83a37660867287869ec1f/height=288;version=1;width=512/http%3A%2F%2Fnginx.org%2Fnginx.png)