[SR-Users] B2BUA removing a=nortpproxy:yes (rtpproxy-1 <---RTP---> rtpproxy-2)

[Iñaki Baz Castillo]

2010/4/24 Juha Heinanen <jh at tutpro.com>:
> Iñaki Baz Castillo writes:
>
>>   1.6.4.  force_rtp_proxy([flags [, ip_address]])
>  >
>  >     -r   flags that IP address in SDP should be trusted. Without this
>  > flag, nathelper
>  >          ignores address in the SDP and uses source address of the
>  > SIP message
>  >          as media address which is passed to the RTP proxy.
>
> i don't understand what chaining of rtpproxies has to do with trusting
> of ip addresses.  my proxy can receive a request from anyone from the
> internet and if that someone is behind nat and his proxy happens to use
> rtpproxy, then chaining with my rtpproxy does not work if some kind of
> trust relationship between these two proxies is needed.

If these rtpproxy use the same IP as the Kamailio's SIP signalling IP,
then there is no problem and no need to use "-r" flag. But my case is
more exotic as there is a transparent proxy between Kamailio-1 and
Kamailio-2, each one with its own RtpProxy not listening in same IP as
its Kamailio, and thre is also a transaparent SIP proxy between them
which, for some reason, removes the line "a=nortpproxy". In this case
both RtpProxy would handle the media and a deadlock would occur if
flag "-r" is not used because after some timeout both RtpProxy would
start relaying RTP to the IP of the transparent proxy (the prefilled
address when not using "-r" flag).

I've checked it.



-- 
Iñaki Baz Castillo
<ibc at aliax.net>