I&#39;m afraid that this is perfectly legitimate proxy behavior as per RFC.<br>
If your 200 OK contact contains a FQDN as domain part, the ACK will have it<br>
in the R-URI and Kamailio will forcefully have to resolve it before<br>
relaying and there is no guarantee that the result will be the same.<br>
Also don&#39;t forget that ACK is a transaction on its own, if you want to<br>
track down things between INVITE transaction and ACL transaction you have<br>
to use an &quot;external&quot; mechanism, like can using dialog module or htable<br>
module.<br>
<br>
<br>
On Tue, Jul 2, 2019 at 10:55 AM Surendra Tiwari &lt;notifications@github.com&gt;<br>
wrote:<br>
<br>
&gt; Description<br>
&gt;<br>
&gt; We are converting udp call to tcp call in kamailio. kamailio sending out<br>
&gt; an invite to a destination. Before sending, kamailio resolving that<br>
&gt; destination domain to IP. After receiving invite request, Destination send<br>
&gt; 180 and 200 OK . 200 Ok contact contains the domain name of destination.<br>
&gt; After this kamailio forward those request to next route. kamailio recieved<br>
&gt; the ack from upstream. After reciving the ack from upstream it resolves<br>
&gt; again the domain name to different IP, as domain name have 2 IP&#39;s behind.<br>
&gt; Troubleshooting Reproduction Debugging Data<br>
&gt;<br>
&gt; (paste your debugging data here)<br>
&gt;<br>
&gt; Log Messages<br>
&gt;<br>
&gt; (paste your log messages here)<br>
&gt;<br>
&gt; SIP Traffic<br>
&gt;<br>
&gt; (paste your sip traffic here)<br>
&gt;<br>
&gt; Possible Solutions Additional Information<br>
&gt;<br>
&gt;    - *Kamailio Version* - output of kamailio -v<br>
&gt;<br>
&gt; (paste your output here)<br>
&gt;<br>
&gt;<br>
&gt;    - *Operating System*:<br>
&gt;<br>
&gt; (paste your output here)<br>
&gt;<br>
&gt; —<br>
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