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List:       openser-users
Subject:    [SR-Users] Re: DNS resolution with ipops
From:       Henning Westerholt <hw () gilawa ! com>
Date:       2023-05-22 14:44:01
Message-ID: AM0PR07MB38737B1748BAFC1C1A53B94ABF439 () AM0PR07MB3873 ! eurprd07 ! prod ! outlook ! com
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[Attachment #2 (text/plain)]

Hello,

the function dns_query(..) just uses getaddrinfo() function, so it does not use the \
internal Kamailio cache. It would do a DNS resolution to the configured resolver for \
each call. The TTL will be irrelevant in this scenario for Kamailio.

Cheers,

Henning

From: harneet singh <hbilling@gmail.com>
Sent: Sonntag, 21. Mai 2023 13:35
To: Kamailio (SER) - Users Mailing List <sr-users@lists.kamailio.org>
Subject: [SR-Users] DNS resolution with ipops

Hi Experts,

I am planning to use dns_query() API from the ipops module, which I understand from \
some documentation that it internally uses getaddrinfo(). I wanted to check if \
someone can comment on the DNS Cache mechanism in this case.

* Does Kamailio retain any dns cache while using this API, or would it be actually \
doing the resolution for each call.

* In light of the above, does Kamailio honour the TTL value in response to the DNS \
Query?

Regards,
Harneet Singh
--
"Once you eliminate the impossible, whatever remains, no matter how improbable, must \
be the truth" - Sir Arthur Conan Doyle


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<p class="MsoNormal"><span \
style="mso-fareast-language:EN-US">Hello,<o:p></o:p></span></p> <p \
class="MsoNormal"><span \
style="mso-fareast-language:EN-US"><o:p>&nbsp;</o:p></span></p> <p \
class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:EN-US">the function \
dns_query(..) just uses getaddrinfo() function, so it does not use the internal \
Kamailio cache. It would do a DNS resolution to the configured resolver for each \
call. The  TTL will be irrelevant in this scenario for \
Kamailio.<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-GB" \
style="mso-fareast-language:EN-US"><o:p>&nbsp;</o:p></span></p> <p \
class="MsoNormal"><span lang="EN-GB" \
style="mso-fareast-language:EN-US">Cheers,<o:p></o:p></span></p> <p \
class="MsoNormal"><span lang="EN-GB" \
style="mso-fareast-language:EN-US"><o:p>&nbsp;</o:p></span></p> <p \
class="MsoNormal"><span lang="EN-GB" \
style="mso-fareast-language:EN-US">Henning<o:p></o:p></span></p> <p \
class="MsoNormal"><span lang="EN-GB" \
style="mso-fareast-language:EN-US"><o:p>&nbsp;</o:p></span></p> <div \
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<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm \
0cm;font-size:pt"> <p class="MsoNormal"><b><span lang="EN-GB">From:</span></b><span \
lang="EN-GB"> harneet singh &lt;hbilling@gmail.com&gt; <br>
<b>Sent:</b> Sonntag, 21. Mai 2023 13:35<br>
<b>To:</b> Kamailio (SER) - Users Mailing List \
&lt;sr-users@lists.kamailio.org&gt;<br> <b>Subject:</b> [SR-Users] DNS resolution \
with ipops<o:p></o:p></span></p> </div>
</div>
<p class="MsoNormal"><o:p>&nbsp;</o:p></p>
<div>
<p class="MsoNormal">Hi&nbsp;Experts,<o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p>&nbsp;</o:p></p>
</div>
<div>
<p class="MsoNormal">I am planning to use <b>dns_query</b>() API from the ipops \
module, which I understand&nbsp;from some documentation that it internally uses \
<b>getaddrinfo</b>().&nbsp;<o:p></o:p></p> </div>
<div>
<p class="MsoNormal">I wanted to check if someone can comment on the DNS Cache \
mechanism in this case.&nbsp;<o:p></o:p></p> </div>
<div>
<p class="MsoNormal"><o:p>&nbsp;</o:p></p>
</div>
<div>
<p class="MsoNormal">* Does Kamailio retain any <b>dns cache</b> while using this \
API, or would it be actually doing the resolution for each call.<o:p></o:p></p> \
</div> <div>
<p class="MsoNormal"><o:p>&nbsp;</o:p></p>
</div>
<div>
<p class="MsoNormal">* In light of the above, does Kamailio honour the <b>TTL value \
i</b>n response to the DNS Query?<o:p></o:p></p> </div>
<div>
<p class="MsoNormal"><o:p>&nbsp;</o:p></p>
</div>
<div>
<p class="MsoNormal">Regards,<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Harneet Singh<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><span class="gmailsignatureprefix">-- </span><o:p></o:p></p>
<div>
<p class="MsoNormal">&quot;Once you eliminate the impossible, whatever remains, no \
matter how improbable, must be the truth&quot; - Sir Arthur Conan \
Doyle<o:p></o:p></p> </div>
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