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</o:shapelayout></xml><![endif]--></head><body lang=DE link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>Hi,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>I’ve setup FreeSWITCH (using FusionPBX) to connect to the German Telekom using their SIP-Trunk product.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>Basically everything works fine except I have to restart the external SIP Profile every 1-2 weeks because of a 403 FORBIDDEN message returned by the Telekom server.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>After some investigation I think I know why this happens, but I have no idea how to solve it.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>The DNS SRV records from the Telekom return 3 servers with different priorities.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>- You can check that with: nslookup -querytype=SRV _sip._tcp.reg.sip-trunk.telekom.de<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>FreeSWITCH takes the one with the highest prio and registers.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>- e.g. serverA<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>- Also every 240 seconds a re-registration happens<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>Then everything works as expected<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>- All INVITES go to serverA as well (because reg.sip-trunk.telekom.de is also the outbound proxy)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>Once in a while the Telekom changes the prio of the servers<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>- So the next INVITE goes to serverB<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>- And this is where I get the 403 because they expect the INVITE to be sent to the server FreeSWITCH registered before (in this example serverA)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>So I see two problems here I’d like to solve:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>When re-registering every 240 seconds it looks like FreeSWITCH doesn’t do another DNS lookup and doesn’t re-register to the server with highest prio<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>- How can I force FreeSWITCH to do this DNS lookup before every registration and choose the new “best” server?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>- How can I force FreeSWITCH to send the INVITES to the server it registered before (and not to the one with the currently highest prio)?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>When doing some research I found the 3CX has some new option implemented especially for this problem: “Force invites to be send to IP of registrar”<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>Please see: <a href="https://www.3cx.de/blog/deutsche-telekom-sip-trunk-wichtig/">https://www.3cx.de/blog/deutsche-telekom-sip-trunk-wichtig/</a><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>Is something like this also possible with FreeSWITCH?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'>Thanks, Klaus<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Lucida Sans Unicode",sans-serif'><o:p> </o:p></span></p></div></body></html>