[Pdns-users] recursor failing to pick up change in master .ca zone file
b.candler at pobox.com
Mon Nov 16 16:17:21 UTC 2020
On 16/11/2020 15:35, Eric Beck via Pdns-users wrote:
> The recursor was still one .ca master zone file behind
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
> , even after
> plenty of time had elapsed.
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.
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:
;; ANSWER SECTION:
ca. 3585 IN SOA prdpublish04.cira.ca.
admin-dns.cira.ca. 2011161530 1800 900 3456000 *3600*
> Any idea why this would happen? Is there some setting that would result
> in this sort of behaviour?
Most likely TTL, unless you can show evidence to the contrary. You can
use rec_control dump-cache
<https://doc.powerdns.com/recursor/manpages/rec_control.1.html> to dump
the entire cache contents to disk.
Note: the PDNS recursor has multiple levels of cache, including a
"packet cache" which is a shortcut when exactly the same query packet is
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
But even those will resolve themselves when the record expires.
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