-------------------PBX THAT DOES NOT WORK--------------------------
<------------->
--- (8 headers 0 lines) ---
Retransmitting #1 (no NAT) to 54.172.60.0:5060:
OPTIONS sip:54.172.60.0 SIP/2.0
Via: SIP/2.0/UDP 74.143.153.122:5060;branch=z9hG4bK5a2ff431
Max-Forwards: 70
From: "+18124254246" <sip:+18124254246@74.143.153.122>;tag=as7b52d616
To: <sip:54.172.60.0>
Contact: <sip:+18124254246@74.143.153.122:5060>
Call-ID: 50a862224f92d38a48fded355e53f4f7@74.143.153.122
CSeq: 102 OPTIONS
User-Agent: Asterisk PBX 11.10.0
Date: Fri, 03 Apr 2015 17:15:31 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
Supported: replaces, timer
Content-Length: 0


---

<--- SIP read from UDP:54.172.60.0:5060 --->
SIP/2.0 200 OK
Via: SIP/2.0/UDP 74.143.153.122:5060;branch=z9hG4bK5a2ff431
From: "+18124254246" <sip:+18124254246@74.143.153.122:5060>;tag=as7b52d616
To: <sip:54.172.60.0>;tag=b7d4d466679e40db21e520d3d781e8c8.744e
Call-ID: 50a862224f92d38a48fded355e53f4f7@74.143.153.122:5060
CSeq: 102 OPTIONS
Server: Twilio Gateway
Content-Length: 0

<------------->
--- (8 headers 0 lines) ---


--------------------- PBX THAT *DOES* WORK ---------------------------------
---
Reliably Transmitting (no NAT) to 54.172.60.0:5060:
OPTIONS sip:54.172.60.0 SIP/2.0
Via: SIP/2.0/UDP 162.209.63.132:5060;branch=z9hG4bK01970b60
Max-Forwards: 70
From: "18448562412" <sip:+18448562412@162.209.63.132>;tag=as65faeb35
To: <sip:54.172.60.0>
Contact: <sip:+18448562412@162.209.63.132:5060>
Call-ID: 27737e16067d03bc13c876ea6e79bfc1@162.209.63.132
CSeq: 102 OPTIONS
User-Agent: Asterisk PBX 11.16.0
Date: Fri, 03 Apr 2015 17:10:29 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLIS                                                                             H, MESSAGE
Supported: replaces, timer
Content-Length: 0


<--- SIP read from UDP:54.172.60.0:5060 --->
SIP/2.0 200 OK
Via: SIP/2.0/UDP 162.209.63.132:5060;branch=z9hG4bK01970b60
From: "18448562412" <sip:+18448562412@162.209.63.132>;tag=as65faeb35
To: <sip:54.172.60.0>;tag=b7d4d466679e40db21e520d3d781e8c8.bc40
Call-ID: 27737e16067d03bc13c876ea6e79bfc1@162.209.63.132
CSeq: 102 OPTIONS
Server: Twilio Gateway
Content-Length: 0