[OpenSIPS-Users] Media proxy basic setup

[Raúl Alexis Betancor Santana]

On Friday 16 October 2009 21:41:56 Daniel Goepp wrote:
> Unfortunately yes, in this situation I am.  The firewall is not PAT, but
> rather a full 1 to 1 NAT.  So any request coming in on port 10000 or 10001
> will go straight to MP.  From a network perspective I know it works as long
> as the application is aware of what's going on.  I'm able to get FreeSWITCH
> running next to this and it handles the packets fine, but FS has a way to
> tell it what the external IP is.  Trust me, I know I'm fighting an uphill
> battle here...but I'm trying to do some proof of concept work that would
> depend on this setup.  And at some point I will just admit defeat, I'm just
> not there yet.  I have gone through the source for MP, and it actually
> doesn't seem like it would be too much to change, but unfortunately I'm no
> Python expert.

Changing mediaproxy code will not fix your problem, beleive me ... mediaproxy 
works inserting conntrack rules on the kernel, it doesn't open any port.

Continue with the previous example ... RTP flow will be like ..

UAC1 -> RTP to 222.222.222.222:10000 -> NAT 1:1 Router -> 10.10.10.10:10000
-> 10.10.10.10:10001 -> NAT Router -> UAC2

Who assure you that the NAT Router will map the outoing RTP stream as 
222.222.222.222:10001 that is what UAC2 is specting ? anyone, because NAT 1:1 
mapping are for INCOMING from outsideworld to insideworld ... but not for 
OUTGOING RTP flows ..

Taking into account that on the near-end routers (UAC's side) will 
not "magicaly" open any port or something similiar ... you will end 99 of 100 
times with a OWA (One Way Audio) situation.

That's why mediaproxy and rtpproxy was designed to work on public IP's, for 
avoiding deadlocks on RTP forwarding and to be able to work even if near-end 
routers doesn't map RTP flow correctly.

-- 
Raúl Alexis Betancor Santana
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