<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span></span>When two users have registered themselves with FS, either user can send a SIP SIMPLE MESSAGE request to the other via FS.<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span></span>
<div><br>
</div>
<div>For example, Alice and Bob are both registered so Alice can send a message to Bob and vice versa.<br>
</div>
<div><br>
</div>
<div>However, my use-case is slightly different. Only Alice is registered; Bob is a device at some unknown location on the internet on a NATed network behind a firewall/gateway.<br>
</div>
<div><br>
</div>
<div>Bob is able to send a SIP MESSAGE request to Alice@Domain.com and it will be received by FS then forwarded to Alice.<br>
</div>
<div><br>
</div>
<div>My question is how can Alice get a reply MESSAGE back to Bob when he hasn't registered? By default, if Alice tries to reply to Bob@Domain.com, FS will send back a 202/Accepted to Alice, but the message will go nowhere.<br>
</div>
<div><br>
</div>
<div>Given that when Bob sends his message to Alice, the source address of his message will be valid for a short period (therefore the source address is the return address), how can I ensure that when Alice sends a reply MESSAGE a second or two later, it gets
to Bob?<br>
</div>
<div><br>
</div>
<div>My initial thought was to somehow auto-register Bob in FS using the source address of his message. Then Alice's reply should get there. Is this possible? Or should Alice's reply be sent another way? I think the reply to Bob must come from the same address
to which he sent his message.<br>
</div>
<div><br>
</div>
<span>Some additional info:</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span><br>
</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span>Alice never initiates a conversation to Bob, but will always send one reply message to any message from Bob.</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span><br>
</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span>Bob actually represents up to a few thousand devices at various locations on the internet. These devices may send a single unsolicited message at any time and expect a reply message within a few seconds.</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span><br>
</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span>---</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span><br>
</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt">
<span>I also tried to do this with Kamailio, but couldn't find a way to auto-register Bob - or save his location in the location db - in order to send back a reply (and Kamailio returns a 404 to Alice rather than 202).</span></div>
</span><br>
</div>
</body>
</html>