Turning on Signaling NAT Traversal in OpenSER

loadmodule "nathelper.so"
modparam("nathelper", "rtpproxy_disable", 1)

if (uri==myself) {
force_rport();

if (method=="INVITE") {

if (nat_uac_test("7")) {
fix_nated_contact();
};
}

route(1);
};
route[1] {

t_on_reply("1");

# send it out now; use stateful forwarding as it works reliably
# even for UDP2TCP
if (!t_relay()) {
sl_reply_error();
};
exit;
}

onreply_route[1] {

if (nat_uac_test("1")) {
fix_nated_contact();
};
}