[Kamailio-Users] Having problems using RTPProxy to bridge internal/external networks

[Örn Arnarson]

Hi Alex,

Can you give an example of code for the rtpproxy_offer/answer
functions so that I can try them out and see whether the SDP
substitution happens? Because, as you may remember from my last mail,
the bridging is working for me, but the substitution isn't.

Regards,
Örn

2009/10/15 Alex Balashov <abalashov at evaristesys.com>:
> An update on this:  we've gotten the SDP substitution to happen correctly
> using rtpproxy_offer()/answer(), and the media endpoints now send their
> media to the correct respective interface addresses on the rtpproxy host.
>
> However, despite allegedly running in "bridge mode" (-l one.ip/two.ip), the
> rtpproxy does not appear to be "bridging" them - that is, it is not
> forwarding.
>
> We previously found that having /proc/sys/net/ipv4/ip_forward on was an
> issue, so we turned it on - but to no effect.
>
> Alex Balashov wrote:
>
>> Örn Arnarson wrote:
>>
>>> Oh, I forgot one thing;
>>>
>>> I'm using fix_nated_sdp, as previously mentioned. I have a hunch that
>>> because I'm not using force_rtp_proxy/rtpproxy_offer it's not being
>>> relayed (a hunch, because I don't fully understand how rtpproxy
>>> works). Problem is though, I can't get the IP addresses correct by
>>> using rtpproxy_offer.
>>
>> On behalf of Joe (same company) I will add that there is no NAT scenario
>> here.  Both the private and public network are directly routable from the
>> rtpproxy box;  there is no IP address oversubscription, and no reason to
>> ignore ports or addresses in SDP and replace them with received parameters.
>>  This is not a far-end NAT traversal solution.
>>
>> What is basically being asked here is how to bridge between two interfaces
>> (internal, external) without NAT using rtpproxy, and if anyone can provide a
>> canonical implementation or example.
>>
>> We've got it running in bridge mode, e.g.
>>
>>  rtpproxy -F -s udp:10.x.x.x:5050 -l 10.x.x.x/89.y.y.y
>>
>> ... and basically, are just wondering how to get this to work on the
>> Kamailio side using rtpproxy_offer()/rtpproxy_answer().
>>
>> The RTP proxy machine is a dedicated host;  the SIP proxies are virtual.
>>
>>
>
>
> --
> Alex Balashov - Principal
> Evariste Systems
> Web     : http://www.evaristesys.com/
> Tel     : (+1) (678) 954-0670
> Direct  : (+1) (678) 954-0671
>