Ok confusion is reigning supreme, different networks, sipsorcery installs, devices, it's all too much for my little head.
I think it would make things simpler to stick to the sipsorcery.com server and try and identify the problem with it.
If you don't get audio on your side it most likely means the IP socket in the Ok response from your device is wrong.
The portion of your trace below is showing the response sent to sipgate with the SDP from your phone/device. The ONLY thing the sipsorcery server has done to the SDP is to swap the private IP address it contained, 10.56.239.98, to the public one the sipsorcery.com server received the request from, 166.137.10.200. When one way audio occurs it is usually because the port your device specified to receive audio on, in this case 4002, gets translated by the NAT to a different port and therefore any audio sipgate tries to send it will be rejected. With a double NAT there are double the chances of the port being translated.
DialPlan=> Response 200 OK for sip:SS-User@166.137.10.200:35934;transport=UDP.
DialPlan=> SDP on UAC response had RTP socket mangled from 10.56.239.98:4002 to 166.137.10.200:4002.
DialPlan=> Cancelling all call legs for ForkCall app.
SIPTransaction=> Send Final Response Reliable udp:10.248.58.129:5070->10.248.58.129:5060
SIP/2.0 200 Ok
Via: SIP/2.0/UDP 10.248.58.129:5060;branch=z9hG4bK63539fac31cc0056bfcee44546d944397675b49a
Via: SIP/2.0/UDP 198.65.166.131;branch=z9hG4bK661.af7480a3.1
Via: SIP/2.0/UDP 198.65.166.131;branch=z9hG4bK661.9f7480a3.0
Via: SIP/2.0/UDP 198.65.166.147:5060;branch=z9hG4bK4b7d4ad3;rport=5060
To: <sip:747253XXXX@198.65.166.131>;tag=1035991471
From: "704375XXXX" <sip:704375XXXX@198.65.166.147>;tag=as751ce8c8
Call-ID: 0fbd818f7dd6e47306c9f71e56eb090e@198.65.166.147
CSeq: 102 INVITE
Contact: <sip:10.248.58.129:5070>
Record-Route: <sip:198.65.166.131;lr;ftag=as751ce8c8>,<sip:198.65.166.131;lr;ftag=as751ce8c8>
Server:
www.sipsorcery.com
Content-Length: 220
Content-Type: application/sdp
v=0
o=- 3472238488 3472238489 IN IP4 10.56.239.98
s=pjmedia
c=IN IP4 166.137.10.200
t=0 0
a=X-nat:0
m=audio 4002 RTP/AVP 0 101
a=rtpmap:0 PCMU/8000
a=sendrecv
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
What would be useful is to see a packet capture of a call directly from one of your devices to sipgate over the AT&T network. I'd like to see what it's doing differently to enable the sipgate RTP to be able to get back through the double NAT.
Regards,
Aaron