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    <font face="monospace">Thank you Giovanni for starting this.<br>
      <br>
      So, the feature should focus on generating the PRACK requests.
      Maybe this should be decoupled from the `100rel` management, as
      this can be received or locally inserted. And you can easily do it
      from script:<br>
<a class="moz-txt-link-freetext" href="https://opensips.org/html/docs/modules/3.6.x/sipmsgops.html#func_list_hdr_add_option">https://opensips.org/html/docs/modules/3.6.x/sipmsgops.html#func_list_hdr_add_option</a><br>
      <br>
      The result here should be a dlg dedicated function to generate a
      PRACK from the onreply_route, like "dlg_answer_with_prack()" kind
      of function? or should we look into a more automatic approach,
      like flagging the dialog at creation to automatically generate the
      PRACK upon replies flagged with so?<br>
      <br>
      Regards,<br>
    </font>
    <pre class="moz-signature" cols="72">Bogdan-Andrei Iancu

OpenSIPS Founder and Developer
  <a class="moz-txt-link-freetext" href="https://www.opensips-solutions.com">https://www.opensips-solutions.com</a>
  <a class="moz-txt-link-freetext" href="https://www.siphub.com">https://www.siphub.com</a></pre>
    <div class="moz-cite-prefix">On 25.11.2025 11:46, Giovanni
      Maruzzelli wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CALXCt0o5NsyQ2LZxBEzmqcit7TqPGcXwDX9_a+zkGnuWToyT0A@mail.gmail.com">
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          <div>hello OpenSIPSers,</div>
          <div><br>
          </div>
          <div>in previous mails has been noticed that various ITSPs are
            starting to require PRACK support.</div>
          <div><br>
          </div>
          <div>We know that PRACK belongs to endpoints, specifically
            phones and B2BUAs.</div>
          <div><br>
          </div>
          <div>But...</div>
          <div><br>
          </div>
          <div>There can be a use case where OpenSIPS will work as SBC
            (not necessarily using the b2b module)</div>
          <div><br>
          </div>
          <div>So, we can have a case where we would like to support
            that the dialogue module insert the 100rel in the Supported:
            INVITE's header, and manage to send a PRACK method to
            acknowledge provisional responses</div>
          <div><br>
          </div>
          <div>If and when 100rel/PRACK are "generated" by OpenSIPS,
            they will be filtered out (not propagated) to/from the
            endpoints, even if the endpoint would like to support it</div>
          <div><br>
          </div>
          <div>Reference RFC: <a
              href="https://www.ietf.org/rfc/rfc3262.txt"
              target="_blank" moz-do-not-send="true"
              class="moz-txt-link-freetext">https://www.ietf.org/rfc/rfc3262.txt</a></div>
          <div><br>
          </div>
          <div>I believe this will be enough to make ITSPs happy.</div>
          <div><br>
          </div>
          <div>Further developments can be moved to future.</div>
          <div><br>
          </div>
          <div>Would be very very nice to have this feature backported
            to OpenSIPS 3.6, being it the last of the 3.X series, and an
            LTS</div>
          <div><br>
          </div>
          <div>Please let's gather here your thoughts , requests,
            corrections and observations on this issue.</div>
          <div><br>
          </div>
          <div>Have a nice Monday you all!</div>
          <font color="#888888">
            <div><br>
            </div>
            <div>-giovanni</div>
          </font></div>
        <div><br>
        </div>
        <span class="gmail_signature_prefix">-- </span><br>
        <div dir="ltr" class="gmail_signature"
          data-smartmail="gmail_signature">Sincerely,<br>
          <br>
          Giovanni Maruzzelli<br>
          OpenTelecom.IT<br>
          cell: +39 347 266 56 18<br>
          <br>
        </div>
      </div>
      <br>
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