Incoming SIP calls dropped after ~30 seconds FIXED

I am new to freepbx from an Trixbox background.

I recently got into a situation where I have needed to reconfigure my switch from scratch (HD failure in the previous one) and found that Trixbox CE is no longer available and so I switched to freepbx. The network configuration is the same WRT internal NATted IP addresses, DID providers, port forwarding etc. Prior to the drive failure this worked well, but since the upgrade, I have all incoming calls dropped after about 30 seconds or so.

I think I have tracked the problem down to the invite message (which I have included a sanitized version of at the bottom of the message) setting the ‘c’ parameter to its internal address, instead of the public address of my router. I have set what I think are the most likely settings that affect this as below, but to no benefit. Is there anything else I can try?

SIP settings, external address is set to my external static ip address and local network configured to the local network (192.168.1.0/255.255.255.0)
Chan SIP, Nat configuration NAT = Yes, Ip Configuration = Static IP, Override External IP = (external address from previous page greyed out)

The trunk is configured as follows

username=
fromuser=
type=friend
secret=
host=incoming.future-nine.com
insecure=port,invite
nat=yes
qualify=yes
context=from-trunk ; change for proper context
allow=ulaw,g729,g726
trustrpid=yes
sendrpid=yes
canreinvite=no

[2014-12-19 09:44:26] VERBOSE[5500] chan_sip.c: Retransmitting #6 (NAT) to X.X.X.244:5060:
SIP/2.0 200 OK
Via: SIP/2.0/UDP X.X.X.244:5060;branch=z9hG4bK41525444;received=X.X.X.244;rport=5060
From: "TOFT ANTHONY " sip:[email protected];tag=as76df6925
To: (sip details);tag=as47321629
Call-ID: [email protected]
CSeq: 102 INVITE
Server: FPBX-12.0.19(11.14.2)
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
Supported: replaces, timer
Contact: sip:[email protected]:5060
Content-Type: application/sdp
Content-Length: 283

v=0
o=root 1419552449 1419552449 IN IP4 192.168.1.12
s=Asterisk PBX 11.14.2
c=IN IP4 192.168.1.12
t=0 0
m=audio 10900 RTP/AVP 0 18 101
a=rtpmap:0 PCMU/8000
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20
a=sendrecv

You have your external and internal networks set to the same subnet? That is wrong.

Sorry for the ambiguity, my external address is set to the public address of my router, the internal address is set to 192.168.1.0/255.255.255.0

To close the loop…

For some reason I rebooted the machine and when it came back up it was working as expected.