[Serusers] RTP being sent to wrong port

[Andrey Kuprianov]

   Hi,

Im facing this problem for a few days already. Hope someone might have
an idea or two. It's a long email too, btw.

Im testing my app behind NAT's with SER-0.9.6 + mediaproxy + Asterisk
(conf server). While X-Lite works *fine* and I get 2 way audio always,
my app seems to have some kind of weird bug and I end up with 1 way
audio stream.

Here's the thing. Application starts receiver and transmitter on
completely different ports. Here's SDP for remote and local machines
(public IP's been x'ed by myself, of course):

This one's sent in INVITE message to SER ==>
69563 DEBUG media.MediaManager - Local SDP: (this one's from local machine)
v=0
o=xps 1158739216750 1158739216757 IN IP4 192.168.1.3
s=MC
c=IN IP4 192.168.1.3
t=0 0
m=audio 25000 RTP/AVP 0 8
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=sendrecv

This one's sent with 200 OK from SER ==>
69563 DEBUG media.MediaManager - Remote SDP:
v=0
o=root 2500 2500 IN IP4 203.159.x.x
s=session
c=IN IP4 203.159.x.x
t=0 0
m=audio 30004 RTP/AVP 0 8
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=silenceSupp:off - - - -

The further log shows that transmitters and receivers have started on
the proper IP/port ==>

69594 DEBUG media.AVReceiver -  Start listening for RTP @ addr:
192.168.1.3 port: 25000 ttl: 1
69657 DEBUG media.AVTransmitter - Created transmitter for:
[203.159.x.x] at ports: [30004] encoded as: [[ULAW/rtp, alaw]]
69657 DEBUG media.MediaManager - Starting transmission
69672 DEBUG media.AVTransmitter - Track 0 is set to transmit as:
ULAW/rtp, 8000.0 Hz, 8-bit, Mono, FrameSize=8 bits
69860 INFO media.AVTransmitter - Binded to port 30004
69875 DEBUG media.AVTransmitter - Started transmitting track 0 encoded
as ULAW/rtp @ [203.159.x.x]:30004

Nevertheless, the Ethereal capture shows that mediaproxy sends the
stream NOT to port 25000 (local port), but to port 30004 (remote
port)!! Why? This is not the case with X-Lite, however. Xlite captures
show that streams are sent to proper ports always. Btw, Im attaching
SIP+RTP Ethereal captures with this mail. Please, take a look.

I also want to mention, that this doesnt happen with my app. for all
the NATed nets. In some nets it works fine, but not in this one. Just
weird.

Please, let me know if anyone has ideas or hints regarding this nonsence :)

   Bests,

    Andrey.
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