auto4certbot/nginx_examples/nginx/templates/proxy.conf

proxy_redirect              off;
proxy_set_header            Host $host;
proxy_set_header            X-Real-IP $remote_addr;
proxy_set_header            X-Forwarded-For $proxy_add_x_forwarded_for;
client_max_body_size        10m;
client_body_buffer_size     128k;
proxy_connect_timeout       90;
proxy_send_timeout          90;
proxy_read_timeout          90;
proxy_buffer_size           4k;
proxy_buffers               4 32k;
proxy_busy_buffers_size     64k;
proxy_temp_file_write_size  64k;