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

[Reda Aouad]

Thanks Richard for the tip :)

Reda



On Sun, Jun 24, 2012 at 7:28 PM, Richard Brady <rnbrady at gmail.com> wrote:

> Hi Reda
>
> A bit late for a reply but I found your post recently and it helped me
> to solve a similar problem, so I wanted to share one possible
> solution.
>
> On 21 January 2012 23:19, Reda Aouad <reda.aouad at gmail.com> wrote:
> > 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.
>
> One way to get around this is to populate the RR with a hostname
> instead of an address. Then you can configure it so that the external
> clients resolve public_ip but the Kamailio server itself resolves
> private_ip. This can be done through an entry in /etc/hosts to
> override the public DNS entry.
>
> Not exactly elegant but it works for me.
>
> > 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)
>
> Regards,
> Richard
>
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