Not possible since t.38 doent take place over RTP!<span></span><br><br>On Sunday, March 22, 2015, Bill Ross <<a href="mailto:rossbcan@gmail.com">rossbcan@gmail.com</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="EN-CA" link="blue" vlink="purple"><div><p class="MsoNormal">Folks;<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">I am attempting to deploy T.38 Fax (ZRTP Secure) with FreeSwitch / FusionPBX and am seeking system architectural advice regarding how to approach this.<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal"><span style="color:red">Question #1:</span> Recommended T.38 capable ATA (and settings) for reliable FAX.<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal"><span style="font-size:14.0pt">Approach #1 ZRTP mitm with T.38 SIP Extension (either T.38 capable ATA or soft endpoint) – preferred approach<u></u><u></u></span></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">T.38 SIP endpoint <-> FS#1 / mitm <-> cloud <-> FS#2 mitm <-> T.38 SIP endpoint<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">I am using a soft T.38 SIP endpoint, plugin for Windows Fax and Scan from faxback, available here:<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal"><a href="http://www.faxback.com/Products/Trialware.aspx?NET_SAT_EDITION=Small%20Business" target="_blank">http://www.faxback.com/Products/Trialware.aspx?NET_SAT_EDITION=Small%20Business</a><u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">SIP Gateway, just prior to bridge:<u></u><u></u></p><p class="MsoNormal" style="margin-left:36.0pt"><strong><span style="font-family:"Calibri","sans-serif""><action application="export" data="fax_enable_t38_request=true"/></span></strong><br><strong><span style="font-family:"Calibri","sans-serif""><action application="set" data="execute_on_answer=t38_gateway peer"/><u></u><u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif""><u></u> <u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif"">Extension, just prior to bridge:<u></u><u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif""><u></u> <u></u></span></strong></p><p class="MsoNormal" style="margin-left:36.0pt"><strong><span style="font-family:"Calibri","sans-serif""><action application="set" data="fax_enable_t38_request=true"/></span></strong><br><strong><span style="font-family:"Calibri","sans-serif""><action application="set" data="execute_on_answer=t38_gateway self"/><u></u><u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif""><u></u> <u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif"">What I am seeing (two FS systems), each with T.38 soft extensions, attempting to fax each other.<u></u><u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif""><u></u> <u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif""> ZRTP negotiation fails (Max retransmissions fail) -> NOZRTP<u></u><u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif""> ONE SDP is T38Fax (extension or gateway), Other is PCMU/8000<u></u><u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif""> The extension of T.38 enters state [ready] and immediately hangs up, I assume from SDP mismatch<u></u><u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif""><u></u> <u></u></span></strong></p><p class="MsoNormal"><span style="color:red">Question #2:</span> Anyone successfully done this, if so, how?<span style="color:red"><u></u><u></u></span></p><p class="MsoNormal"><span style="color:red">Question #3:</span> Is what I am attempting architecturally possible? Can T.38 be mitm’d?<u></u><u></u></p><p class="MsoNormal"><span style="color:red">Question #4:</span> If so, advice regarding how to debug the ZRTP negotiation failure and SDP negotiation failure.<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal"><span style="font-size:14.0pt">Approach #2: FS terminates incoming T.38 fax, stores and forwards to fax extension, FS terminates outgoing T.38 fax, stores and forwards to SIP gateway to final destination.<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:14.0pt"><u></u> <u></u></span></p><p class="MsoNormal">T.38 SIP endpoint <-> FS#1 / terminate fax <-> FS#1 forward fax <-> cloud <-> FS#2 / terminate fax <-> FS#2 forward fax <-> T.38 SIP endpoint<u></u><u></u></p><p class="MsoNormal"><span style="font-size:14.0pt"><u></u> <u></u></span></p><p class="MsoNormal"><span style="color:red">Question #5: </span><span style="color:black">Will this work? Anyone done it, how? ZRTP gotcha’s?</span><strong><span style="font-family:"Calibri","sans-serif""><u></u><u></u></span></strong></p><p class="MsoNormal"><strong><span style="font-family:"Calibri","sans-serif""><u></u> <u></u></span></strong></p><p class="MsoNormal">Thanks;<u></u><u></u></p><p class="MsoNormal">Bill<u></u><u></u></p></div></div></blockquote><br><br>-- <br><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr">
<p><font face="courier new, monospace"><b><i><font size="4">Brian West</font></i></b><br><span style="font-size:x-small"><a href="mailto:brian@freeswitch.org" target="_blank">brian@freeswitch.org</a></span></font></p>
<p><font size="1" face="courier new, monospace"><img src="http://billing.freeswitch.org/templates/default/img/whmcslogo.png"><br></font></p><p><font face="courier new, monospace"><b><i>Twitter: @FreeSWITCH , @briankwest</i></b><br><a href="http://www.freeswitchbook.com" target="_blank">http://www.freeswitchbook.com</a><br><a href="http://www.freeswitchcookbook.com" target="_blank">http://www.freeswitchcookbook.com</a></font></p><p>ClueCon 2015 <a href="https://www.cluecon.com/call-for-speakers/" target="_blank">Call for Speakers</a> | <a href="https://freeswitch.com/cart.php?gid=1" target="_blank">Register</a> TODAY!</p>
<p><font face="courier new, monospace"><b>T:</b>+19184209001 | <b>F:</b>+19184209002 | <b>M:</b>+1918424WEST (9378)<br><b>iNUM:</b>+883 5100 1420 9001 | <b>ISN:</b>410*543 | <b>Skype:</b>briankwest</font></p></div></div></div></div></div><br>