27 Apr
2023
27 Apr
'23
6:11 p.m.
On 27/04/2023 11.08, [EXT] Kiss Zoltán wrote:
Everything is working fine, but with some clients (like Grandstream
phone) the RTCP session wants to go tot he private address of the
phone. Here is the log of one of these strange calls:
Apr 27 16:54:38 rtp1 rtpengine[2273]: INFO:
[312ed76c31f21b71452e91e5184ad25b@172.16.2.210:5060]: [core] ---------
Port 178.238.213.14:11088 <> 81.183.216.3:5068 , SSRC 77c19488, 625
p, 107500 b, 0 e, 29 ts
Apr 27 16:54:38 rtp1 rtpengine[2273]: INFO:
[312ed76c31f21b71452e91e5184ad25b@172.16.2.210:5060]: [core] ---------
Port 178.238.213.14:11089 <> 10.0.5.192:5069 (RTCP), SSRC 0, 0 p, 0
b, 0 e, 43 ts
As you can see the RTP itself is okay, but the RTCP will somehow go to
the private address. If we tracing the sdp messages in sngrep, then we
can see that Kamailio transforming IP addresses for the backend
servers to the public (and the private address of the rtpengine)
addresses.
This is almost certainly because the client has not /sent/ any RTCP, and
therefore rtpengine was not able to learn the correct public non-NAT
address for the RTCP port, leaving you with the address that was
advertised in the SDP.
Cheers