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<p class="MsoNormal">I am new to OpenSIPS and I am trying to configure it as SBC between MS Teams (with TLS connection) and a FreePBX/Asterisk server (with UDP connection) with a private IP address.<o:p></o:p></p>
<p class="MsoNormal">In order for MS Teams to send the ACK to 200 OK reply through the same TLS connection it used to send INVITE request I have to configure OpenSIPS to send Contact header with URI containing its FQDN instead of its IP address. Unfortunately
topology_hiding module sets IP address, so MS Teams tries to create a new TLS connection and most probably refuses the certificate, because it contains FQDN, not IP address.<o:p></o:p></p>
<p class="MsoNormal">I tried several approaches with configuring OpenSIPS:<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">-<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>changed socket to be with FQDN and alias with IP address – topology hiding still sets IP address in Contact header<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">-<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>tried to add manually second contact header – it was not recognized by MS Teams (it still used the first one and tries to create a new TLS connection) and I could not add thinfo parameter, needed by topology_hiding module<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Is there another module in OpenSIPS which allows modifying Contact URI only of a reply?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Also I think that I have to add record-route header in my 200 OK reply, according to OpenSIP how-to:<o:p></o:p></p>
<p class="MsoListParagraph" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">
<b><span style="font-size:12.0pt;font-family:"Times New Roman",serif">UPDATE:</span></b><span style="font-size:12.0pt;font-family:"Times New Roman",serif"> Starting from 01.07.2020 Microsoft requires Route headers with SBC_FQDN in SIP replies too. Instead of
simple record_route() for SIP request from MS servers OpenSIPS should add FQDN, but in different order:<o:p></o:p></span></p>
<p class="MsoListParagraph"><span style="font-size:10.0pt;font-family:"Courier New"">record_route_preset("LAN_IP:5060", "SBC_FQDN:5061;transport=tls");<o:p></o:p></span></p>
<p class="MsoListParagraph"><span style="font-size:10.0pt;font-family:"Courier New"">add_rr_param(";r2=on");<o:p></o:p></span></p>
<p class="MsoNormal">I tried to add it in the main route script before calling topology_hiding() in order for it to be restored on replies, but this didn’t work:<o:p></o:p></p>
<p class="MsoNormal"><span style="color:#5B9BD5">record_route_preset("sbc.tbgit.com:5067;transport=tls");<o:p></o:p></span></p>
<p class="MsoNormal">I noticed that topology_hiding creates a branch, so I tried to add the same record_route_preset in the branch_route also, but this didn’t help – I just receive:<o:p></o:p></p>
<p class="MsoNormal"><span style="color:#5B9BD5">ERROR:rr:w_record_route_preset: Double attempt to record-route<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any help is welcome.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Peter<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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Data Classification: <b>Confidential </b></div>
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