[kareztt]

We use windstream as an ISP, they provide a SIP trunk. Callers from inside can be heard outside, but not the other way around. It does not make a difference as to who originated the call. To make matters more interesting I can hear the inbound audio using wireshark on the phone server when I look at the SIP and RTP traffic. But nothing but the sounds of silence on the soft phones. IT jsut seems that the 3cx system is not accepting or ignoring the inbound audio for some reason. I am at a total loss on this and would appreciate any suggestions anyone has.

Thanks
Tom

[leejor]

Did this issue just start, or has it never worked properly?
What type of router/firewall are you using?
Did you forward all of the ports required?
Did you run the 3CX firewall checker? Did everything pass?

[kareztt]

It has never worked.
I have tested the firewall and it tested correctly.
5060 tcp/udp and 9000-10000 udp and 40000-50000 (rpt per isp) are forwarded to 3cx box.
It is limksys rv082. Mid-low end router.
Had this same issue without the router.

Here is some additional info.
For the SIP trunk, we PBX delivered enabled. Should be necessary.

If I take 2 soft phones and set them to to PBX delivered it also delivers no audio. Is there is an issue with the PBX handling audio?

[kareztt]

Found the issue, the SDP section of the INVITE was listing the the 3cx box's local IP. This resulted in the ISP not sending the correct RTP responses, once I changed the SDP IP in the advanced config section all is well at last.

Tom