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<TITLE>Far-end NAT traversal and anti-tromboning with FS</TITLE>
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<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Ah, t</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">he joys of NAT</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">…</FONT></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Is</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">FS</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">’</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> NAT functionality supposed to be able to detect and handle far-end NAT traversal?</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">I have the following scenario:</FONT></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Endpoints on a LAN connected via the Internet to FS though</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">NAT</FONT></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">FS -</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">-</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">></FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> Internet --></FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> NAT</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">firewall</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">--> Endpoints</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Proxying the media works fine but w</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">hen attempting to bypass media between endpoints all on the same LAN,</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">I would expect FS to negotiate media between them using their internal IP addresses. So if IP phone A at 10.0.0.101 wants to talk to IP phone B at 10.0.0.102,</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">FS</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">sh</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">ould set up the media streams to go directly between them using those internal addresses. However, that is not the behavior I</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">’</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">m seeing. Instead, FS is trying to set up the media between them using their external IP addresses</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> which results in no audio.</FONT></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Is there a way to get FS to handle this properly? I</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">’</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">m pretty sure that OpenSIPS</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">’</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> can detect and handle this scenario</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> and I</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">’</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">m hoping that FS can as well, without having to put OpenSIPS in front of it. </FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">Is this just a configuration issue?</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Many thanks,</FONT></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><I></I></SPAN><SPAN LANG="en-us"><I></I></SPAN><I><SPAN LANG="en-us"></SPAN></I><I><SPAN LANG="en-us"><FONT FACE="Times New Roman">Phil Quesinberry</FONT></SPAN></I><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
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