[Kamailio-Users] Kamailio and RTPProxy

[Daniel-Constantin Mierla]

Hello,

On 12/14/09 4:54 PM, Bruce McAlister wrote:
> Hi Daniel,
>
>    
>> depending on flags, the public or internal IP is used to update the sdp.
>> If you get it in the wrong order, then change the flags e and i in
>> force_rtp_proxy() call.
>>
>>      
> I think I have the flags setup correctly because I am able to get calls
> working if I setup a phone to send out its details as having my firewall
> ip address. If I change the ei/ie parameters in force_rtpproxy then the
> calls dont work at all.
>
> I will try to explain my scenario below.
>
> I have a soft phone (x-lite) on my pc who's internal IP address is
> 192.168.11.2. When I initiate a call from my softphone the contact
> address is setup as 192.168.11.2, kamailio then adds the rport and
> received parameters as my external firewall ip and port.
>
> When I force the rtpproxy setup, it looks like rtpproxy is setting up
> the correct ports on our publice ip, but it looks like rtpproxy wants to
> talk to my softphone using ip address 192.168.11.2 instead of the ip
> address that is in the recevied parameter.
>
> INFO:handle_command: pre-filling caller's address with 192.168.11.2:14880
>
> My external IP of my firewall is 188.141.20.76, I would have expected
> the rtpproxy line to look like this:
>
> INFO:handle_command: pre-filling caller's address with 188.141.20.76:14880
>
> The media server on the other side of the rtpproxy bridge is able to
> send traffic to rtpproxy, but it looks like rtpproxy is not able to
> contact the softphone as it is a private address.
>
> If I do the same test using a Cisco 7960 which has "nat-traversal"
> enabled in its configuration then the call works, rtpproxy sets up the
> correct ports on the internal nic for the media server to talk to and it
> sets up a port pair on its external nic to talk to the cisco phone. This
> works.
>
> I suspect my problem lies with nat somewhere and telling rtpproxy to use
> the "recieved" ip address of my firewall to talk to my x-lite.
>
> I hope I am explaining my scenario better. Any comments suggestions
> would be appreciated.
>    

in order to connect the rtp stream, rtpproxy needs to receive an audio 
packet (rtp) from each side. rtpproxy main job is to give addresses and 
ports to fill in SDP of INVITE and 200OK reply.

If you can get an ngrep trace with such call, I can give more hits about 
whether is ok or not.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
* http://www.asipto.com/