Hello,<br>I&#39;m trying to understand this sample cfg:<br><a href="http://voip-info.org/wiki/view/OpenSER+And+RTPProxy" target="_blank">http://voip-info.org/wiki/view/OpenSER+And+RTPProxy</a><br><br>This cfg is used as foundation for some of our cfg files here but nobody is sure about exactly how some things work. So I&#39;m trying to clear things up.<br>

In particular, I am clueless about why there is code removing &quot;nat=yes&quot; from the URI and adding it to the Contact header (actually I don&#39;t know what is its meaning. I suppose this is a way of a client advertising that it is behind NAT, but I couldn&#39;t find which RFC defines this):<br>

<br>subst_uri(&#39;/(sip:.*);nat=yes/\1/&#39;)<br><br>search_append(&#39;Contact:.*sip:[^&gt;[:cntrl:]]*&#39;, &#39;;nat=yes&#39;);<br><br>Is this something that always must be done when dealing with nat or it was a particular situation that the writer of the cfg had to workaround? <br>

I&#39;m rewriting our cfg file (to be used with m4) and I&#39;m trying to remove unnecessary things.<br><br>Another thing in the cfg: in case a reinvite is issued, should not unforce_rtp_proxy be called before force_rtp_proxy is called again? Could this lead to having rtpproxy leaking resources?<br>

<a style="background-color: rgb(255, 255, 255);" href="http://www.kamailio.org/docs/modules/1.3.x/nathelper.html#AEN367" target="_blank"></a><br>
regards,<br>mayama<br><br>