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<div class="moz-cite-prefix">On 16/11/2020 15:35, Eric Beck via
Pdns-users wrote:<br>
</div>
<blockquote type="cite"
cite="mid:d5c6f391-8c2f-4601-db48-ff297e4f4f4d@cadns.ca">
<pre class="moz-quote-pre" wrap="">The recursor was still one .ca master zone file behind</pre>
</blockquote>
<p>I'm not sure what you mean by "one .ca master zone file behind".
The recursor doesn't copy the zone file; it reads (and caches)
individual records.<br>
</p>
<blockquote type="cite"
cite="mid:d5c6f391-8c2f-4601-db48-ff297e4f4f4d@cadns.ca">
<pre class="moz-quote-pre" wrap="">, even after
plenty of time had elapsed.</pre>
</blockquote>
<p>Can you show the actual output for "dig" against the recursor for
the record in question? The dig output should have shown a TTL,
and that TTL should have been decrementing towards zero, after
which it would have been refreshed from one of the authoritative
servers for the domain.</p>
<p>Or were you getting NXDOMAIN for the query (for a newly-created
domain?) Negative answers are also cached. The .ca SOA record
says they can be cached for one hour:</p>
<p>;; ANSWER SECTION:<br>
ca. 3585 IN SOA prdpublish04.cira.ca.
admin-dns.cira.ca. 2011161530 1800 900 3456000 <b>3600</b><br>
</p>
<p><br>
</p>
<p>
</p>
<blockquote type="cite"
cite="mid:d5c6f391-8c2f-4601-db48-ff297e4f4f4d@cadns.ca">
<pre class="moz-quote-pre" wrap="">
Any idea why this would happen? Is there some setting that would result
in this sort of behaviour?</pre>
</blockquote>
<p>Most likely TTL, unless you can show evidence to the contrary.
You can use <a moz-do-not-send="true"
href="https://doc.powerdns.com/recursor/manpages/rec_control.1.html">rec_control
dump-cache</a> to dump the entire cache contents to disk.<br>
</p>
<p>Note: the PDNS recursor has multiple levels of cache, including a
"packet cache" which is a shortcut when exactly the same query
packet is seen again.</p>
<p>This can lead to some odd situations, where client A sees one
answer repeatedly with a 'dig', but client B sees a different
answer. This can happen if client A and client B asked with
different flags, so get mapped to different entries from the
packet cache, and the authoritative answer changed between client
A making the request and client B making the request.</p>
<p>But even those will resolve themselves when the record expires.</p>
<p>Regards,</p>
<p>Brian.<br>
</p>
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