[Serusers] PSTN gateway doubt

Luca Corti cortez at tiscali.it
Fri Feb 4 15:08:26 CET 2005


On Fri, 2005-02-04 at 11:23 +0100, Daniel-Constantin Mierla wrote:
> if it works is correct :-) ... this depends mainly on how the AS is 
> configured, what domains it accepts in request URI. The statement you 
> pasted from docs can be used for outbound proxies, the incoming message 
> is not changed, just delivered to the address from the parameters.

Trying to use t_relay_to_[udp|tcp] fails on my setup. That's not a
problem until it works :)

My problem now is that when SER handles calls from PSTN (PSTN -> AS5350
-> SER -> SIP-UA ) the call fails. The SIP-UA rings and I can pick the
call up, but the PSTN phone still rings and doesn't establish the call.

Sniffing traffic through ethereal discloses that the 183 SDP I see in
successful calls is not present.

Any ideas?

thanks

Here's my ser.cfg


#
# $Id: ser.cfg,v 1.21.4.1 2003/11/10 15:35:15 andrei Exp $
#
# simple quick-start config script
#

# ----------- global configuration parameters ------------------------

listen=$SER_PUBLIC_IP
listen=127.0.0.1

alias=cdlan.net
alias=$SER_PUBLIC_IP

# Uncomment these lines to enter debugging mode
debug=7
fork=no
log_stderror=yes

check_via=no
dns=no
rev_dns=no
#port=5060
#children=4
fifo="/tmp/ser_fifo"

# ------------------ module loading ----------------------------------

# Uncomment this if you want to use SQL database

loadmodule "/usr/lib/ser/modules/mysql.so"
loadmodule "/usr/lib/ser/modules/sl.so"
loadmodule "/usr/lib/ser/modules/tm.so"
loadmodule "/usr/lib/ser/modules/rr.so"
loadmodule "/usr/lib/ser/modules/maxfwd.so"
loadmodule "/usr/lib/ser/modules/usrloc.so"
loadmodule "/usr/lib/ser/modules/registrar.so"
loadmodule "/usr/lib/ser/modules/textops.so"
loadmodule "/usr/lib/ser/modules/uri.so"
loadmodule "/usr/lib/ser/modules/nathelper.so"
loadmodule "/usr/lib/ser/modules/auth.so"
loadmodule "/usr/lib/ser/modules/auth_db.so"
loadmodule "/usr/lib/ser/modules/acc.so"
loadmodule "/usr/lib/ser/modules/group.so"

# ----------------- setting module-specific parameters ---------------

# -- usrloc params --

# Uncomment this if you want to use SQL database for persistent storage
modparam("usrloc", "db_mode", 2)

# Autenticazione al db
modparam("usrloc", "db_url", "sql://ser:s3r@localhost/ser")

# -- auth params --
# Uncomment if you are using auth module
#
modparam("auth_db", "calculate_ha1", yes)
#
# If you set "calculate_ha1" parameter to yes (which true in this
config),
# uncomment also the following parameter)
#
modparam("auth_db", "password_column", "password")

# secret
modparam("auth", "secret", "mysecret")

# Autenticazione al db
modparam("auth_db", "db_url", "sql://user:pass@localhost/ser")

# Autenticazione al db
modparam("group", "db_url", "sql://user:pass@localhost/ser")

# -- rr params --
# add value to ;lr param to make some broken UAs happy
modparam("rr", "enable_full_lr", 1)

# Autenticazione al db
modparam("uri", "db_url", "sql://user:pass@localhost/ser")

# Autenticazione al db
#modparam("vm", "db_url", "sql://user:pass@localhost/ser")

# !! Nathelper
modparam("registrar", "nat_flag", 6)
modparam("nathelper", "natping_interval", 30) # Ping interval 30 s
modparam("nathelper", "ping_nated_only", 1)   # Ping only clients behind
NAT

# -------------------------  request routing logic -------------------

route{

        # initial sanity checks -- messages with
        # max_forwards==0, or excessively long requests
        if (!mf_process_maxfwd_header("10")) {
                sl_send_reply("483","Too Many Hops");
                break;
        };
        if ( msg:len > max_len ) {
                sl_send_reply("513", "Message too big");
                break;
        };

        # we record-route all messages -- to make sure that
        # subsequent messages will go through our proxy; that's
        # particularly good if upstream and downstream entities
        # use different transport protocol
        record_route();
        # loose-route processing
        if (loose_route()) {
                t_relay();
                break;
        };

        # !! Nathelper
        # Special handling for NATed clients; first,NAT test is
        # executed: it looks for via!=received and RFC1918 addresses
        # in Contact (may fail if line-folding is used); also,
        # the received test should, if completed, should check all
        # vias for rpesence of received if (nat_uac_test("3")) {
        # Allow RR-ed requests, as these may indicate that
        # a NAT-enabled proxy takes care of it; unless it is
        # a REGISTER

        if (method == "REGISTER" || ! search("^Record-Route:")) {
                log("LOG: Someone trying to register from private IP,
rewriting\n");

                # This will work only for user agents that support
symmetric
                # communication. We tested quite many of them and
majority is
                # smart enough to be symmetric. In some phones it takes
a configuration
                # option. With Cisco 7960, it is called NAT_Enable=Yes,
with kphone it is
                # called "symmetric media" and "symmetric signalling".

                fix_nated_contact(); # Rewrite contact with source IP of
signalling
                if (method == "INVITE") {
                        fix_nated_sdp("1"); # Add direction=active to
SDP
                };
                force_rport(); # Add rport parameter to topmost Via
                setflag(6);    # Mark as NATed
        };

        # we record-route all messages -- to make sure that
        # subsequent messages will go through our proxy; that's
        # particularly good if upstream and downstream entities
        # use different transport protocol
        if (!method=="REGISTER") record_route();

        # subsequent messages withing a dialog should take the
        # path determined by record-routing
        if (loose_route()) {

                # mark routing logic in request
                append_hf("P-hint: rr-enforced\r\n");
                route(1);
                break;

        };

        # if the request is for other domain use UsrLoc
        # (in case, it does not work, use the following command
        # with proper names and addresses in it)
        if (uri==myself) {

                if (method=="REGISTER") {

                        # Uncomment this if you want to use digest
authentication
                        if (!www_authorize("cdlan.net", "subscriber")) {

                                www_challenge("cdlan.net", "0");
                                break;

                        };

                        save("location");
                        break;

                };


                if (method=="INVITE" &&
uri=~"^sip:[^6][0-9]*@cdlan.net") {

                        append_hf("P-hint: PSTN\r\n");
                        rewritehostport("10.0.1.20:5060");
                        route(1);
                        break;

                };

                lookup("aliases");

                # native SIP destinations are handled using our USRLOC
DB
                if (!lookup("location")) {
                        sl_send_reply("404", "Not Found");
                        break;
                };

        };

        append_hf("P-hint: usrloc applied\r\n");

        route(1);

}

# -- relay calls --
route[1]
{

        if (uri=~"[@:](192\.168\.|10\.|172\.(1[6-9]|2[0-9]|3[0-1])\.)"
&& !uri=~"[@:]10\.0\.1\.20" && !search("^Route:")){
                sl_send_reply("479", "We don't forward to private IP
addresses");
                break;
        };

        # if client or server know to be behind a NAT, enable relay
        if (isflagset(6)) {
                force_rtp_proxy();
        };

        # NAT processing of replies; apply to all transactions (for
example,
        # re-INVITEs from public to private UA are hard to identify as
        # NATed at the moment of request processing); look at replies
        t_on_reply("1");

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

                sl_reply_error();

        };

}
onreply_route[1] {
        # NATed transaction ?
        if (isflagset(6) && status =~ "(183)|2[0-9][0-9]") {
                fix_nated_contact();
                force_rtp_proxy();
                # otherwise, is it a transaction behind a NAT and we did
not
                # know at time of request processing ? (RFC1918
contacts)
        } else if (nat_uac_test("1")) {
                fix_nated_contact();
        };

}





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