[SR-Users] SIP routing problem when kamailio uses 2 interfaces

[Klaus Darilion]

I think you have multiple issues:

(not sure if I am right as I have to guess your network setup)

1. If Kamailio is an Application Layer Gateway between the public and 
the internal network, then of course Asterisk should listen only on the 
internal interface. Thus in sip.conf add:

   udpbindaddr = internal.ip.add.ress

Further you can tweak if Asterisk should use internal or public IP 
addresses inside the SIP message headers by playing around with
   externip = ...
   localnet = ...

2. Regardless of the Via header inserted by Kamailio Asterisk should 
respond to the IP address from which Kamailio sent the request. Thus I 
guess Kamailio sent the request with the public IP address as source IP.

To have Kamailio acting correctly you have to make sure that Kamailio is 
listening on both interfaces 
(http://sip-router.org/wiki/cookbooks/core-cookbook/devel#listen):

   listen=udp:public.ip.add.ress:5060
   listen=udp:internal.ip.add.ress:5060

and activate multihoming feature of Kamailio to have proper IP addresses 
in Via and Record-Route headers 
(http://sip-router.org/wiki/cookbooks/core-cookbook/devel#mhomed)

   mhomed=1

regards
Klaus

Am 22.08.2010 04:46, schrieb Gnaneshwar Gatla:
> Hello All,
>
> I'm using Kamailio as a Border controller for my VoIP Research project at my
> school.
> The problem I'm facing is Kamailio routes the traffic to the private network
> where my asterisk machine is listening.
> The asterisk machine responds to the Kamailio using the public network but
> not the private. Is this an issue with Asterisk? If so how do I resolve it?
>
>        client	kam_public    Kam_pvt      Ast_pvt    Ast_public
> 	|			|		|		|
> |
> 	|			|		|		|
> |
> 	|    INVITE		|		|		|
> |
> 	|---------------->|		|    INVITE	|		|
> 	|			|		|---------->|		|
> 	|			|		|		|
> |
> 	|			|		|		|
> |
> 	|			|		|		|
> |
> 	|			|		|     404	|
> |
> 	|			|<----------|-----------|-----------|
> 	|			|		|		|
> |
> 	|			|		|     ACK	|
> |
> 	|			|		|---------->|		|
> 	|			|		|		|
> |
> 	|     404		|		|		|
> |
> 	|<----------------|		|		|		|
> 	|			|		|		|
> |
> 	|     ACK		|		|		|
> |
> 	|---------------->|		|		|		|
> 	|			|		|		|
> |
> 	|			|		|		|
> |
>
>
> Regards
> Gnaneshwar
>
>
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