<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<style>
<!--
@font-face
{font-family:"Cambria Math"}
@font-face
{font-family:Calibri}
@font-face
{font-family:Tahoma}
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif"}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline}
a:visited, span.MsoHyperlinkFollowed
{color:purple;
text-decoration:underline}
p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{margin:0cm;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif"}
span.EmailStyle17
{font-family:"Calibri","sans-serif";
color:windowtext}
span.BalloonTextChar
{font-family:"Tahoma","sans-serif"}
.MsoChpDefault
{}
@page WordSection1
{margin:2.0cm 42.5pt 2.0cm 3.0cm}
div.WordSection1
{}
-->
</style>
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal">Hello All,</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">DNS server configuration:</p>
<p class="MsoNormal">Host – ESXi VM</p>
<p class="MsoNormal">CPU – 4 cores @ 2GHz</p>
<p class="MsoNormal">RAM – 2GB</p>
<p class="MsoNormal">Pdns-recursor – PowerDNS Recursor 3.3</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Currently, the cache and packet cache are set to 1000000 limit by configuration:</p>
<p class="MsoNormal"> max-cache-entries=1000000</p>
<p class="MsoNormal">max-packetcache-entries=1000000</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">As I understood from provided configuration, this is a per thread configuration, and actually we’ll have 4000000 records if 4 threads are used.</p>
<p class="MsoNormal">Now, our caches are full, as can be seen from rec_control:</p>
<p class="MsoNormal"> rec_control get cache-entries packetcache-entries</p>
<p class="MsoNormal"> 1001003</p>
<p class="MsoNormal"> 1001090</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">My questiones are what is the behavior of pdns-recursor if a new request, not known by the recursor, is issued by our clients?</p>
<p class="MsoNormal">What will it do with the received response? </p>
<p class="MsoNormal">Is it OK to have the caches full all the time? We see that many of our clients are issuing requests for non-existing domains, filling the cache with NXDOMAIN records.</p>
<p class="MsoNormal">Where can I read more about this process?</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Thank you.</p>
</div>
This message and attached information may be confidential. It is intended only for the use of the individual or entity named above. If you have received this message in error you are hereby notified that any dissemination, distribution or copying of this communication
is strictly prohibited, and please immediately notify us by telephone or reply by e-mail and then promptly delete the message. Thank you for your cooperation.
</body>
</html>