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    <div class="moz-cite-prefix">Hello,</div>
    <div class="moz-cite-prefix"><br>
    </div>
    <div class="moz-cite-prefix">from SIP specs point of view, can be
      any port -- ACK and BYE do not have to follow same path as INVITE,
      so they can even come from a different IP.<br>
    </div>
    <div class="moz-cite-prefix"><br>
    </div>
    <div class="moz-cite-prefix">Then, the call can be closed after
      30secs because also the ACK has the same problems with the header
      as the BYE. Your pcap didn't include all the traffic, you have to
      capture both directions on your kamailio server to see what
      happens on each side.</div>
    <div class="moz-cite-prefix"><br>
    </div>
    <div class="moz-cite-prefix">Cheers,<br>
      Daniel<br>
    </div>
    <div class="moz-cite-prefix"> </div>
    <div class="moz-cite-prefix"><br>
    </div>
    <div class="moz-cite-prefix"><br>
    </div>
    <div class="moz-cite-prefix">On 06.11.20 10:35, Kjeld Flarup wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CACRoYp8ozDeBwABcDdh4+rzcnpMPS3dR1Ydhv9qF9-nm+b_GTQ@mail.gmail.com">
      <meta http-equiv="content-type" content="text/html; charset=UTF-8">
      <div dir="ltr">
        <div dir="ltr">Hi Daniel
          <div><br>
          </div>
          <div>The Unknown Dialog comes because the server hang up the
            call 30 seconds earlier. We never gets these BYE messages,
            thus the door phone hangs times out and hangs up.</div>
          <div><br>
          </div>
          <div>My question is still, which port is the BYE from the
            server supposed to be sent to?</div>
          <div><br>
          </div>
          <div>The original 37148</div>
          <div>The new 37150</div>
          <div>or the advertised 5071</div>
          <div><br>
          </div>
          <div>Regards Kjeld</div>
        </div>
        <br>
        <div class="gmail_quote">
          <div dir="ltr" class="gmail_attr">Den fre. 6. nov. 2020 kl.
            10.18 skrev Daniel-Constantin Mierla <<a
              href="mailto:miconda@gmail.com" moz-do-not-send="true">miconda@gmail.com</a>>:<br>
          </div>
          <blockquote class="gmail_quote" style="margin:0px 0px 0px
            0.8ex;border-left:1px solid
            rgb(204,204,204);padding-left:1ex">
            <div>
              <p>Hello,</p>
              <p>I think you hunt a mirage problem here by looking at
                the ports of tcp connections, if you think that being
                different ports is the cause of BYE failure. The ACK fpr
                200ok is independent of the INVITE transaction and can
                have a completely different path than INVITE, thus is
                completely valid to use another connection. Of course,
                if follows the same path as INVITE, if the connection is
                still open, it should be reused. But is a matter of
                matching, it can be that the INVITE uses different
                destination identifiers or the connection gets cut from
                different reasons. But the point is that even if there
                is a different connection, it should work.</p>
              <p>So, I actually looked at the pcap capture you sent in
                one of your previous emails and the BYE is sent out, but
                gets back:</p>
              <p>SIP/2.0 481 Unknown Dialog.</p>
              <p>Therefore it gets to the end point, which doesn't match
                it with any of its active calls. Looking at the headers,
                the 200ok/INVITE has:</p>
              <p>From: "Front Door"
                <a moz-do-not-send="true"><sip:32221660@194.255.22.44:5071></a>;tag=thm9OFNQemH0IsqgRR1jDGF4rjVivTOK.<br>
                To: <a moz-do-not-send="true"><sip:004540294149@127.0.0.1:5071></a>;tag=12003375157297.<br>
                Call-ID:
                ***FgXBdt966gypC5V1T5VGUtLILtzxsJJ57NRSL5UMUiq*.</p>
              <p>And the BYE:</p>
              <p>From: "Front Door" <a moz-do-not-send="true"><sip:u0@192.168.2.9></a>;tag=thm9OFNQemH0IsqgRR1jDGF4rjVivTOK.<br>
                To:
                <a moz-do-not-send="true">sip:195.249.145.198:5060;transport=udp;line=sr-z-yMngm27FwI73qx0CQo6gm2n3ao03LMn5UILt2NziWIO3ooTDc*;tag=12003375157297</a>.<br>
                Call-ID:
                ***FgXBdt966gypC5V1T5VGUtLILtzxsJJ57NRSL5UMUiq*.</p>
              <p>While the dialog should be matched on call-id,
                from/to-tags, the From/To URI should be the same to be
                strict conformant with RFC3261 (that mandates unchanged
                From/To for backward compatibility with RFC2543). Likely
                you do some From/To header changes that are not done
                correctly to update/restore the values for traffic
                within dialog.</p>
              <p>Cheers,<br>
                Daniel<br>
              </p>
              <div>On 06.11.20 09:31, Kjeld Flarup wrote:<br>
              </div>
              <blockquote type="cite">
                <div dir="ltr">Thanks Juha
                  <div><br>
                  </div>
                  <div>That makes it somehow easier to understand my
                    capture. My Kamailio must then have detected a
                    broken TCP connection, though I cannot see why in
                    the capture, neither in the log, but I only run on
                    debug level 2.</div>
                  <div>It receives a 200 OK on port 37148, and then
                    establishes 37150 to reply with an ACK. </div>
                  <div><br>
                  </div>
                  <div>However two seconds before receiving the 200 OK,
                    there are some spurious retransmissions and out of
                    order on 37148. Perhaps this has caused Kamailio to
                    deem the connection bad, but it still receives data
                    on it.</div>
                  <div>Now I assume that the providers server (Which
                    also is flying Kamailio) should detect the new port,
                    and continue using that. I got a trace from the
                    provider, where there is no disturbance. Thus the
                    server thinks that the connection is OK. </div>
                  <div><br>
                  </div>
                  <div>Now my next question is, what makes a Kamailio
                    detect this change?</div>
                  <div>Is it a problem that I only rewrite To and From
                    in the INVITE, thus the ACK contains some other
                    values. <br>
                  </div>
                  <div><br>
                  </div>
                  <div><br>
                  </div>
                  <div>It is also a bit strange that I get this error
                    exactly, the same place in the conversation every
                    time I make a call. Somehow I suspect some NAT
                    timeout in the router. (it is not carrier grade
                    NAT).</div>
                  <div>Can I do anything to prevent a NAT timeout from
                    the client side?</div>
                  <div><br>
                  </div>
                  <div><br>
                  </div>
                  <div>Another thing. I assume that sending my
                    internal port in the From field, or any kind of
                    advertising, should be ignored by the server.</div>
                  <div><br>
                  </div>
                  <div>Regards Kjeld</div>
                  <div><br>
                  </div>
                  <div><br>
                  </div>
                </div>
                <br>
                <div class="gmail_quote">
                  <div dir="ltr" class="gmail_attr">Den fre. 6. nov.
                    2020 kl. 07.45 skrev Juha Heinanen <<a
                      href="mailto:jh@tutpro.com" target="_blank"
                      moz-do-not-send="true">jh@tutpro.com</a>>:<br>
                  </div>
                  <blockquote class="gmail_quote" style="margin:0px 0px
                    0px 0.8ex;border-left:1px solid
                    rgb(204,204,204);padding-left:1ex">Kjeld Flarup
                    writes:<br>
                    <br>
                    > How is TCP SIP actually supposed to handle a
                    BYE, when the client is <br>
                    > behind NAT.<br>
                    <br>
                    Client behind NAT is supposed to keep its TCP
                    connection to SIP Proxy<br>
                    alive and use it for all requests of the call.  If
                    the connection breaks<br>
                    for some reason, the client sets up a new one for
                    the remaining<br>
                    requests.<br>
                    <br>
                    -- Juha<br>
                    <br>
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                  </blockquote>
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                </div>
                -- <br>
                <div dir="ltr">
                  <div dir="ltr">
                    <p>--------------------- Med Liberalistiske Hilsner
                      ----------------------</p>
                    <pre cols="72">   Civilingeniør, Kjeld Flarup - Mit sind er mere åbent end min tegnebog
   Sofienlundvej 6B, 7560 Hjerm, Tlf: 40 29 41 49
   Den ikke akademiske hjemmeside for liberalismen - <a href="http://www.liberalismen.dk" target="_blank" moz-do-not-send="true">www.liberalismen.dk</a>

</pre>
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                <fieldset></fieldset>
                <pre>_______________________________________________
Kamailio (SER) - Users Mailing List
<a href="mailto:sr-users@lists.kamailio.org" target="_blank" moz-do-not-send="true">sr-users@lists.kamailio.org</a>
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</pre>
              </blockquote>
              <pre cols="72">-- 
Daniel-Constantin Mierla -- <a href="http://www.asipto.com" target="_blank" moz-do-not-send="true">www.asipto.com</a>
<a href="http://www.twitter.com/miconda" target="_blank" moz-do-not-send="true">www.twitter.com/miconda</a> -- <a href="http://www.linkedin.com/in/miconda" target="_blank" moz-do-not-send="true">www.linkedin.com/in/miconda</a>
Funding: <a href="https://www.paypal.me/dcmierla" target="_blank" moz-do-not-send="true">https://www.paypal.me/dcmierla</a></pre>
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        <div><br>
        </div>
        -- <br>
        <div dir="ltr" class="gmail_signature">
          <div dir="ltr">
            <p>--------------------- Med Liberalistiske Hilsner
              ----------------------</p>
            <pre cols="72">   Civilingeniør, Kjeld Flarup - Mit sind er mere åbent end min tegnebog
   Sofienlundvej 6B, 7560 Hjerm, Tlf: 40 29 41 49
   Den ikke akademiske hjemmeside for liberalismen - <a href="http://www.liberalismen.dk" target="_blank" moz-do-not-send="true">www.liberalismen.dk</a>

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      <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>
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</pre>
    </blockquote>
    <p><br>
    </p>
    <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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