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<p>Hello,</p>
<p>there is an option that you can set to reuse the port for tcp/tls
connections, but even so it is a best effort and it is not going
to ensured -- all these are practically flags set to the sockets
and the kernel (tcp stack) decides after all.</p>
<p>Anyhow, the rport is mainly useful for connectionless
communication, like UDP. For tcp/tls, the SIP specs demand to
reuse the existing connections. As I did several Kamailio-MSTeams
interconnectivity deployments, I can tell that the source port was
never a problem. The TLS connection is kept open and MSTeams sends
back traffic on it.<br>
</p>
<p>Cheers,<br>
Daniel<br>
</p>
<div class="moz-cite-prefix">On 08.01.21 14:32, Charles Phillips
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:FCF97D62-9C6E-4B01-9240-93A665EB5D41@rustybike.com">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
Thanks for the quick response Joel. Yes, I have read the article
and I have tested and confirmed that I am correctly appending the
contact header (I probably should have left that in the snippet
for clarity). Below is an example of Kamailio setting up the
connection. It is going out port 46245 this time, but it is
random.
<div class="">
<div class="">
<div class=""><br class="">
</div>
<div class="">
<div class="">07:59:23.572319 IP *my.kamailio.server*.46245
> *ms.teams.server*.sip-tls: Flags [P.], seq 1:518, ack
1, win 502, length 517</div>
<div class="">07:59:23.802458 IP *ms.teams.server*.sip-tls
> *my.kamailio.server*.46245: Flags [P.], seq 1:3767,
ack 518, win 2051, length 3766</div>
<div class=""><br class="">
</div>
<div class="">The TLS connection shows as successful in the
logs.</div>
<div class=""><br class="">
</div>
<div class="">
<div style="color: rgb(0, 0, 0); font-family: Helvetica;
font-size: 12px; font-style: normal; font-variant:
normal; font-weight: normal; letter-spacing: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
word-wrap: break-word; -webkit-nbsp-mode: space;
-webkit-line-break: after-white-space;" class="">
<div class=""><br class="Apple-interchange-newline">
- Charles </div>
<div class=""><br class="">
</div>
<div class=""><br class="">
</div>
</div>
Date: Thu, 7 Jan 2021 19:12:10 -0800<br class="">
From: Joel Serrano <<a href="mailto:joel@textplus.com"
class="" moz-do-not-send="true">joel@textplus.com</a>><br
class="">
To: "Kamailio (SER) - Users Mailing List"<br class="">
<span class="Apple-tab-span" style="white-space: pre;"> </span><<a
href="mailto:sr-users@lists.kamailio.org" class=""
moz-do-not-send="true">sr-users@lists.kamailio.org</a>><br
class="">
Subject: Re: [SR-Users] Source Port on TLS OPTIONS from
Dispatcher<br class="">
Message-ID:<br class="">
<span class="Apple-tab-span" style="white-space: pre;"> </span><<a
href="mailto:CAMtXxQnLtEyD=40cwKembxiyj3D778eK=+5JD7sL4CvYbYXF1g@mail.gmail.com"
class="" moz-do-not-send="true">CAMtXxQnLtEyD=40cwKembxiyj3D778eK=+5JD7sL4CvYbYXF1g@mail.gmail.com</a>><br
class="">
Content-Type: text/plain; charset="utf-8"<br class="">
<br class="">
Hi Charles,<br class="">
<br class="">
I don't think your issue is rport, make sure you are
setting the Contact<br class="">
header correctly.<br class="">
<br class="">
Have you checked this blog post:<br class="">
<a href="https://skalatan.de/en/blog/kamailio-sbc-teams"
class="" moz-do-not-send="true">https://skalatan.de/en/blog/kamailio-sbc-teams</a> ?<br
class="">
<br class="">
There is a specific section that talks about how to tell
Kamailio to send<br class="">
the OPTIONS like MS Teams wants them.<br class="">
<br class="">
Good luck,<br class="">
Joel.<br class="">
<br class="Apple-interchange-newline">
</div>
<div><br class="">
<blockquote type="cite" class="">
<div class="">On Jan 7, 2021, at 7:31 PM, Charles
Phillips <<a href="mailto:charles@rustybike.com"
class="" moz-do-not-send="true">charles@rustybike.com</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<meta http-equiv="Content-Type" content="text/html;
charset=UTF-8" class="">
<div style="word-wrap: break-word; -webkit-nbsp-mode:
space; line-break: after-white-space;" class="">
<div class="">
<div style="font-family: Helvetica; font-size:
12px; font-style: normal;
font-variant-ligatures: normal;
font-variant-caps: normal;
font-variant-east-asian: normal;
font-variant-position: normal; font-weight:
normal; letter-spacing: normal; text-align:
start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px; word-wrap:
break-word; -webkit-nbsp-mode: space;
line-break: after-white-space;" class="">Hello
all. As they say in radio, “long time listener,
first time caller”</div>
<div style="font-family: Helvetica; font-size:
12px; font-style: normal;
font-variant-ligatures: normal;
font-variant-caps: normal;
font-variant-east-asian: normal;
font-variant-position: normal; font-weight:
normal; letter-spacing: normal; text-align:
start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px; word-wrap:
break-word; -webkit-nbsp-mode: space;
line-break: after-white-space;" class=""><br
class="">
</div>
<div style="font-family: Helvetica; font-size:
12px; font-style: normal;
font-variant-ligatures: normal;
font-variant-caps: normal;
font-variant-east-asian: normal;
font-variant-position: normal; font-weight:
normal; letter-spacing: normal; text-align:
start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px; word-wrap:
break-word; -webkit-nbsp-mode: space;
line-break: after-white-space;" class="">Anyway,
I am having trouble getting past the following
road block and any help would be greatly
appreciated.</div>
<div style="font-family: Helvetica; font-size:
12px; font-style: normal;
font-variant-ligatures: normal;
font-variant-caps: normal;
font-variant-east-asian: normal;
font-variant-position: normal; font-weight:
normal; letter-spacing: normal; text-align:
start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px; word-wrap:
break-word; -webkit-nbsp-mode: space;
line-break: after-white-space;" class=""><br
class="">
</div>
<div style="font-family: Helvetica; font-size:
12px; font-style: normal;
font-variant-ligatures: normal;
font-variant-caps: normal;
font-variant-east-asian: normal;
font-variant-position: normal; font-weight:
normal; letter-spacing: normal; text-align:
start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px; word-wrap:
break-word; -webkit-nbsp-mode: space;
line-break: after-white-space;" class="">Kamailio
version is 5.4.3 </div>
<div style="font-family: Helvetica; font-size:
12px; font-style: normal;
font-variant-ligatures: normal;
font-variant-caps: normal;
font-variant-east-asian: normal;
font-variant-position: normal; font-weight:
normal; letter-spacing: normal; text-align:
start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px; word-wrap:
break-word; -webkit-nbsp-mode: space;
line-break: after-white-space;" class=""><br
class="">
</div>
<div style="font-variant-ligatures: normal;
font-variant-east-asian: normal;
font-variant-position: normal; text-align:
start; text-indent: 0px; word-wrap: break-word;
-webkit-nbsp-mode: space; line-break:
after-white-space;" class="">When attempting to
use dispatcher to send OPTIONS packets to
several TLS destinations, the packets are
leaving the Kamailio server on random ports.
This is a problem because the servers I am
sending the OPTIONS to (MS Teams) are enforcing
rport so the responses are returned to a port
that Kamailio is not listening on. I have tried
to force the socket in the event route (relevant
parts of snippet below) but it does not appear
to help. I should also mention that I am not
behind NAT and the TLS socket is specified in
the dispatcher attrs. </div>
<div style="font-variant-ligatures: normal;
font-variant-east-asian: normal;
font-variant-position: normal; text-align:
start; text-indent: 0px; word-wrap: break-word;
-webkit-nbsp-mode: space; line-break:
after-white-space;" class="">
<div style="font-family: Helvetica; font-size:
12px; font-style: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing:
normal; text-transform: none; white-space:
normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px;" class=""><br
class="">
</div>
<div class="">event_route[tm:local-request] {<br
class="">
sip_trace();</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
$fs = “tls:**ip-address**:5061”;</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
}</div>
</div>
</div>
<div class=""><br class="">
</div>
<div class="">I have used Kamailio as a TLS server
for many projects, but this is my first time as a
client. I am sure I am missing something.</div>
<div class="">
<div style="font-family: Helvetica; font-size:
12px; font-style: normal;
font-variant-ligatures: normal;
font-variant-caps: normal;
font-variant-east-asian: normal;
font-variant-position: normal; font-weight:
normal; letter-spacing: normal; text-align:
start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px; word-wrap:
break-word; -webkit-nbsp-mode: space;
line-break: after-white-space;" class="">
<div class=""><br
class="Apple-interchange-newline">
- Charles</div>
<div class=""><br class="">
</div>
</div>
<br class="Apple-interchange-newline"
style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant-ligatures:
normal; font-variant-caps: normal;
font-variant-east-asian: normal;
font-variant-position: normal; font-weight:
normal; letter-spacing: normal; text-align:
start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px;">
<br class="Apple-interchange-newline">
</div>
<br class="">
</div>
</div>
</blockquote>
</div>
<br class="">
</div>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<pre class="moz-quote-pre" wrap="">_______________________________________________
Kamailio (SER) - Users Mailing List
<a class="moz-txt-link-abbreviated" href="mailto:sr-users@lists.kamailio.org">sr-users@lists.kamailio.org</a>
<a class="moz-txt-link-freetext" href="https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users">https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users</a>
</pre>
</blockquote>
<pre class="moz-signature" cols="72">--
Daniel-Constantin Mierla -- <a class="moz-txt-link-abbreviated" href="http://www.asipto.com">www.asipto.com</a>
<a class="moz-txt-link-abbreviated" href="http://www.twitter.com/miconda">www.twitter.com/miconda</a> -- <a class="moz-txt-link-abbreviated" href="http://www.linkedin.com/in/miconda">www.linkedin.com/in/miconda</a>
Funding: <a class="moz-txt-link-freetext" href="https://www.paypal.me/dcmierla">https://www.paypal.me/dcmierla</a></pre>
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