Re: [SR-Users] Kamailio : Listening on multiple ports behind NAT

After endless tests, I tried to replace record_route_preset with insert_hf, writing the complete record route headers. A light started to come out of the tunnel.....

Suppose User A is registered to port 53, User B to port 5060.

In the case of double record route, when A sends an INVITE to B, I write the following in the SIP header of the INVITE forwarded to B : Record-Route: sip:public_ip:5060;r2=on;lr=on Record-Route: sip:public_ip:53;r2=on;lr=on

The first transaction, INVITE / 200OK goes well, with Kamailio forwarding packets correctly from the corresponding socket of each user.

The problem arises when User B sends BYE to the 5060 port, with both route headers in the SIP header of the BYE. I get the following error : WARNING: rr [loose.c:747]: no socket found for match second RR

after which Kamailio forwards the BYE from the 5060 socket to User A. User A being registered on port 53, ignores the packet coming with source port 5060. The BYE is never replied to.

I guess that means that Kamailio is not able to find the private_ip:53 socket from the public_ip:53 record-route header. I hope it was clear.

I think there's a fundamental issue with running Kamailio behind NAT and listening on multiple port numbers. Am I the only one suffering from this type of configuration?

(Part of the problem is also tied to dumb ALG NAT routers which try to out-smart SIP servers, without which I wouldn't run Kamailio on multiple ports, and life would be much easier)

RA

On Thu, Jan 19, 2012 at 01:00, Reda Aouad reda.aouad@gmail.com wrote:

Okay, it seems we're on the right track.. BUT

This is my code in the branch_route

    if (is_method("INVITE|SUBSCRIBE")){
            $avp(s:fs) = $fs;
            $avp(s:Rp) = $Rp;
            avp_subst("$avp(s:fs)", "/(.*):(.*):(.*)/\3/");
            #xlog("fs: $avp(s:fs) | Rp: $avp(s:Rp)");
            if ($avp(s:fs) == $avp(s:Rp)) {
                    record_route_preset("PUBLIC_IP:$avp(s:fs)");
                    return;
            }
            record_route_preset("PUBLIC_IP:$avp(s:fs)",

"PUBLIC_IP:$avp(s:Rp)"); } return;

$avp(s:fs) is the outbound socket, on which I apply the avp_subst function to extract only the outbound port number Kamailio should send from. $avp(s:Rp) is the inbound port, the port on which Kamailio received the INVITE. Then if the above port numbers are equal, I do only one record route. If not, I do double record routing, one per port number.

The problem is that for the first branch, everything works fine. But for the subsequent branches, I get the following error : ERROR: rr [rr_mod.c:256]: Duble attempt to record-route

It seems that for subsequent branches, Kamailio detects that it already record routed the first branch, so gives an error and doesn't record route.

Reda