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<p class="MsoNormal"><span lang="EN-US">Hello,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I have a Kamailio machine configured with two interfaces. One public, one private.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Public Address: 10.10.10.10<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Private Address: 192.168.1.10<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Kamailio forwards the SIP packet to another local endpoint: 192.168.1.20<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">When a client sends a SIP packet using TCP to the public address of Kamailio, Kamailio relays the packet using its private interface (private address) to the other endpoint.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">TCP: Client -> 10.10.10.10 -> 192.168.1.10 -> 192.18.1.20<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">When a client sends a SIP packet using UDP to the public address of Kamailio, Kamailio (or the OS) relays the packet using its public interface (public address) to the other endpoint.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">UDP: Client -> 10.10.10.10 -> 10.10.10.10 -> 192.18.1.20<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">In the case of TCP, the source address is 192.168.1.10.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">In the case of UDP, the source address is 10.10.10.10.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Everything is the same in the routing script for both UDP and TCP, except in route[relay] (see below)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Is this normal? What is causing this, the OS or Kamailio?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Route[RELAY] {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> …<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> if($pr =~ "TCP") {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> if (!t_relay_to_tcp()) {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> sl_reply_error();<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> }<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> } else {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> if (!t_relay_to_udp()) {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> sl_reply_error();<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> }<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> }<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">}<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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