server
{
    listen             80;
    server_name    xxx.com;
    index index.html index.htm;
    root    /tmp/xxx;

    location / {
        root    /tmp/xxx;
        proxy_redirect off;
        proxy_set_header Host yyyy.com;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header REMOTE-HOST $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        client_max_body_size 8m;
        client_body_buffer_size 256k;
        proxy_connect_timeout 30;
        proxy_send_timeout 30;
        proxy_read_timeout 60;
        proxy_buffer_size 256k;
        proxy_buffers 4 256k;
        proxy_busy_buffers_size 256k;
        proxy_temp_file_write_size 256k;
        proxy_next_upstream error timeout invalid_header http_500 http_503 http_404;
        proxy_max_temp_file_size 128m;
        proxy_pass    http://yyyy.com;
    }
}