<div dir="ltr">I think you should enable stun function in mobile phone 2 , then it can sent public ip in contact header . Then I think nathelper module with sip proxy module would caused nat signaling problem be solved , but you should add media proxy function to solve media problem in nated circumstance.<table class="" style="border-spacing:0px;color:rgb(119,119,119);font-size:13px"><tbody><tr><td colspan="2" style="padding:0px"><div class="" style="margin:1px 0px 0px 4px;height:18px;color:rgb(0,0,0);vertical-align:top;white-space:nowrap;text-decoration:underline"><br></div></td><td style="padding:0px;width:500px"><br></td></tr></tbody></table></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jan 6, 2016 at 8:02 PM, Rodrigo Pimenta Carvalho <span dir="ltr"><<a href="mailto:pimenta@inatel.br" target="_blank">pimenta@inatel.br</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif">
<p>Dear OpenSIPS-users,</p>
<p><br>
</p>
<p>First of all, happy new year.</p>
<p>I'm still reading about NATs, SIP proxies and SIP, to understand how to solve a question in my project. I'm not expert in TCP, IP, routers, NATs and networks. That is why I would like to get some help here. I guess I'm almost getting the point to solve
it.<br>
</p>
<p><br>
</p>
<p>In my current network topology case I have:</p>
<p><br>
</p>
<p><br>
</p>
<p> Mobile Phone 1 on Internet</p>
<p> / \ |<br>
</p>
<p> | |</p>
<p> | SIP |</p>
<p></p>
<p> | \/ Real IP (Internet)</p>
<p> NAT ------------------------------------------------
<br>
</p>
/\ | 'Nated' IP (Wan)<br>
<p></p>
<p> | |</p>
<p> | SIP |</p>
<p> | |</p>
<p> | |</p>
<p> | \/ </p>
<p> ROUTER ------------------------------------------------
<br>
</p>
<p> /\ | (Lan) <br>
</p>
<p> | SIP |</p>
<p> | |</p>
<p> SIP Proxy OPENSIPS</p>
<p> | |</p>
<p> | SIP |</p>
<p> | |</p>
<p> Mobile Phone 2 on local network <br>
</p>
<p><br>
</p>
<p><br>
</p>
<p>When Phone 2 calls Phone 1, everything is ok. Phone 1 is registered on OpenSIPS with 'Nated' IP, by someway. So, Phone 2 sends INVITE to such IP. When Phone 1 answers with SIP OK, the Contact header filed has the same 'Nated' IP. Then, Phone 2 can send the
ACK to the correct path.</p>
<p><br>
</p>
<p>However, when Phone 1 calls Phone 2 and Phone 2 answer with SIP OK, Phone 1 can't send the ACK, because the Contact header field from SIP OK has the local IP for Phone 2.</p>
<p>It is true because when Phone 2 registers itself on OpenSIPS, the local IP is recorded in the local database table.</p>
<p><br>
</p>
<p>So I have the following questions:</p>
<p><br>
</p>
<p>1 - Can this problem be solved without using the Nat Traversal Module?</p>
<p><br>
</p>
<p>2 - Can NATHELPER module fix the Contact header field (as a I saw this module has functions related with it), when Phone 2 sends SIP OK to Phone 1? If yes, how can such module determine a 'good' IP to put in this header field?</p>
<p><br>
</p>
<p>3 - If Phone 2 uses a stun server, will such phone be registered on OpenSIP with a real IP, won't be? Could it be a solution too?</p>
<p><br>
</p>
<p>Any hint will be very helpful!</p>
<p><br>
</p>
<p>Thanks a lot!</p><span class="HOEnZb"><font color="#888888">
<p><br>
</p>
<p> <br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<div>
<div name="divtagdefaultwrapper">
<div><font size="2">
<div>RODRIGO PIMENTA CARVALHO<br>
Inatel Competence Center<br>
Software<br>
Ph: <a href="tel:%2B55%2035%203471%209200" value="+553534719200" target="_blank">+55 35 3471 9200</a> RAMAL 979<br>
</div>
</font></div>
</div>
</div>
</font></span></div>
</div>
<br>_______________________________________________<br>
Users mailing list<br>
<a href="mailto:Users@lists.opensips.org">Users@lists.opensips.org</a><br>
<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users" rel="noreferrer" target="_blank">http://lists.opensips.org/cgi-bin/mailman/listinfo/users</a><br>
<br></blockquote></div><br></div>