I’ve been missing with this for a while and seem to be missing something. Any suggestions on what is missing here?

Trying to use set_contact_alias() and handle_ruri_alias() from nathelper module and nat_keepalive from nat_traversal module, without registrar.

I had register keepalive working, that has since broke. When register keepalive was working, I was able to place call in either direction but ACK and BYE was not being routed past kamailio.

Registrations are forwarded to the PBX using add_path() and is working.

Also not included below is the routing to the PBX, that is just setting $du and t_relay, and is also working.

Topology is: UA1 -> NAT -> kamailio -> PBX -> UA2

Using default config file as the example, modified with above changes. I also removed RTP config as that is a non-issue.

request_route {

    ……

    # FLAG MESSAGES FROM PBX

        setflag(FLT_PBX);

    route(NATDETECT);

    ……

route[NATDETECT] {

            if (nat_uac_test("19")) {

force_rport();

                        set_contact_alias();

                        nat_keepalive();

            }

            return;

}

route[WITHINDLG] {

            if (!has_totag()) return;

                        if (loose_route()) {

                                    route(DLGURI);

                        } else if ( is_method("ACK") ) {

                                    route(NATMANAGE);

                        } else if ( is_method("NOTIFY") ) {

                                    record_route();

                        }

            route(RELAY);

            exit;

            }

            if (is_method("SUBSCRIBE") && uri == myself) {

                        route(PRESENCE);

                        exit;

            }

            if ( is_method("ACK") ) {

                        if ( t_check_trans() ) {

                                    route(RELAY);

                                    exit;

                        } else {

                                    exit;

                        }

            }

            sl_send_reply("404","Not here");

            exit;

}

route[NATMANAGE] {

        if(isflagset(FLT_PBX)) {

            handle_ruri_alias();

    }

    if(!isflagset(FLT_PBX)) {

        set_contact_alias();

    }       return;

}

route[DLGURI] {

            if(!isdsturiset()) {

                        handle_ruri_alias();

            }

            return;

}

branch_route[MANAGE_BRANCH] {

            route(NATMANAGE);

}

onreply_route[MANAGE_REPLY] {

            if(status=~"[12][0-9][0-9]") {

                        route(NATMANAGE);

            }

}

failure_route[MANAGE_FAILURE] {

            route(NATMANAGE);

            if (t_is_canceled()) exit;

-dan