if (loose_route()) {
    if ((method=="INVITE" || method=="REFER") && !has_totag()) {
      sl_send_reply("403", "Forbidden");
      exit;
  };

  if (method=="INVITE") {
    if (!allow_trusted()) {
      if (!proxy_authorize("", "subscriber")) {
        proxy_challenge("", "0");
        exit;
      } else if (!check_from()) {
        sl_send_reply("403", "Use From=ID");
        exit;
      };
      consume_credentials();

        };

    if (nat_uac_test("19")) {
      setflag(6);
      force_rport();
      fix_nated_contact();      
      force_rtp_proxy();
  };
 };
  route(1);
  exit;
};