location /ping {
    if (-f /l3-disabled.txt) {
        return 503 'Service disabled by admin';
    }
    proxy_connect_timeout 200ms;
    proxy_read_timeout 1;
    proxy_send_timeout 1;
    proxy_pass http://duffman-master;

    tskv_log /var/log/nginx/access.tskv mail-nginx-access-log;
    error_log /var/log/nginx/error.log info;
}
