Issues resolving

Ondřej Holas ondrej.holas at
Mon Jul 4 09:14:23 UTC 2016

Hello Mark,

similar problem can be reproduced on recursive non-forwarding server by
setting "max-cache-ttl" to some low value (in production I have 3600, for
quick reproduction set it to 10) and sending query "in the last second of
TTL", for example:

== code begin ==
while true; do dig -p 5353 @localhost +noauthority
+noadditional 2>/dev/null | grep -E "^www\.seznam\.cz\.|SERVFAIL"; sleep
10.1; done
== code end ==

In addition to SERVFAIL, sometimes it is accompanied with warning:
"checkhints: unable to get root NS rrset from cache: not found" (IMHO, this
should never happen.)

The behavior is reproducible on 9.10.4 and 9.10.4-P1. I am unable to
reproduce it on 9.11.0b1. After a brief look at the source diffs (especially
lib/dns/rbtdb.c) between 9.10.3-P4, 9.10.4(-P1) and 9.11.0b1, it seems to me
like a problem related to changed handling of "just expiring" records in
9.10.4 [RT #41687].



-----Original Message-----
From: bind-users-bounces at
[mailto:bind-users-bounces at] On Behalf Of Mark Andrews
Sent: Monday, June 20, 2016 8:39 AM
To: Thomas Sturm
Cc: bind-users at
Subject: Re: Issues resolving

A fix for this is in review and should be in the next maintainance release.


In message <16A2CDFD-694D-444A-A760-17C9D7517BCD at>, Thomas Sturm
> I am now able to reliably reproduce the behaviour with dig querying 
> 9.10.4-P1 (not 9.9, apparently) with "prefetch 0b

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