<div dir="ltr">Gnana,<div><br></div><div>These both parameters do not affect Router functionality in any way unless AGL(Application layer gateway) is enabled in Router.</div><div>These parameters are introduced in SIP to overcome NATing issue while STUN is not used.</div><div><br></div><div>Lets take an example. UAC is behind NAT.</div><div>When UAC send a Request, Contact and Via contains its local IP/Port as STUN is disabled. As per standard, UAS will send reply on Via which is local IP and not routable.</div><div>As per guidelines for received parameter, if Source IP in IP header and Contact/Via is different, UAS should send reply on Source IP from IP header and add same in Via header with received="" field. By that way, UAC even know its global IP and use same in next transactions.</div><div><br></div><div>When rport is present in Via header of any request, UAS should process source Port same way as IP. It sends reply on global port and inform same in Via header with rport="".</div><div><br></div><div><br></div><div>Hope this helps.</div><div><br></div><div>Regards,</div><div>Saurabh Shah</div><div><br></div><div><br></div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Regards,<div>Saurabh Shah</div></div></div></div>
<br><div class="gmail_quote">On Mon, Sep 25, 2017 at 9:26 PM, Gnana Guru Natarajan <span dir="ltr"><<a href="mailto:gnanaguru3012@gmail.com" target="_blank">gnanaguru3012@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi,<div><br></div><div> What is the purpose of rport and received parameter in sip via header? Will it be needed if sip client is behind NAT router? If so, how router can process this sip header as router only handle the IP header but cannot application layer header?</div><div><br></div><div>Thanks,</div><div>Gnana Guru N.</div></div>
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