2015-06-23 18:49 GMT+03:00 Daniel-Constantin Mierla miconda@gmail.com:
Have you grabbed the sip trace on client side to see what it is receiving? Are the clients reporting errors?
Yes, see this https://gist.github.com/krieger-od/c9fe6ea4bb64fac82cda this is taken on Linux box running Jitsi desktop app. It doesn't report anything, or I haven't seen the log, ut just doesn't show the incoming call.
If you have a snom phone, you can easily see the received sip packets via web interface. Perhaps the desktop phones will have also some logs printing what is happening that can be accessed easily.
Eventually you can try to run a kamailio locally, near the client, using it as an intermediate proxy between the phone and the main sip server.
The timestamps I checked in previous traces were not following the sip retransmissions intervals (0.5sec, 1sec, 2sec, ...), a clear indication that it is not kamailio transaction layer doing retransmissions.
As I said before, ngrep is not a source to trust when dealing with large packets. Also, it can happen that it prints the same packet twice.
But what sniffer should I try instead of ngrep to have more details and confidence?
Also I guess you mean this to be an issue of Linux kernel on any side, or possibly of routing hardware somewhere in the route?