<div dir="ltr">Hey FreeSWITCH Users,<div><br></div><div>Interesting issue here. We&#39;re connecting to Nexmo, a major SIP provider. They do load balancing of their SIP servers; a set of four IPs behind <a href="http://sip.nexmo.com" target="_blank">sip.nexmo.com</a>. </div><div><br></div><div>I have a FS sip set up to register to their server. However, in INVITE, it seems to switch IPs. Basically it goes like this:</div><div><br></div><div>US -&gt; INVITE <a href="http://sip.nexmo.com" target="_blank">sip.nexmo.com</a> (IP1)</div><div>IP1 -&gt; 407 AUTH</div><div>US -&gt; INVITE <a href="http://sip.nexmo.com" target="_blank">sip.nexmo.com</a> (DIFFERENT IP2) nonce and auth stuff</div><div>IP2 -&gt; 904 FAIL</div><div><br></div><div>Here&#39;s my config:</div><div><div>&lt;include&gt;</div><div>  &lt;gateway name=&quot;<a href="http://sip.nexmo.com" target="_blank">sip.nexmo.com</a>&quot;&gt;</div><div>    &lt;param name=&quot;username&quot; value=&quot;XXXXX&quot;/&gt;</div><div>    &lt;param name=&quot;password&quot; value=&quot;YYYYY&quot;/&gt;</div><div>    &lt;param name=&quot;from-user&quot; value=&quot;XXXXX&quot;/&gt;</div><div>    &lt;param name=&quot;from-domain&quot; value=&quot;<a href="http://sip.nexmo.com" target="_blank">sip.nexmo.com</a>&quot;/&gt;</div><div>    &lt;param name=&quot;proxy&quot; value=&quot;<a href="http://sip.nexmo.com" target="_blank">sip.nexmo.com</a>&quot;/&gt;</div><div>    &lt;param name=&quot;expire-seconds&quot; value=&quot;600&quot;/&gt;</div><div>    &lt;param name=&quot;register&quot; value=&quot;true&quot;/&gt;</div><div>    &lt;param name=&quot;retry-seconds&quot; value=&quot;30&quot;/&gt;</div><div>    &lt;param name=&quot;extension&quot; value=&quot;5000&quot;/&gt;</div></div><div>...</div><div><br></div><div>How do we stop this from happening? Setting from-domain and proxy to an IP behind their load balancer fixes it, but that&#39;s clearly suboptimal. Why is FS resolving the <a href="http://sip.nexmo.com" target="_blank">sip.nexmo.com</a> DNS twice?</div><div><br></div><div>Thanks!</div></div>