Resolver failures after stale-answer enabled

[Blažej Krajňák]

https://gitlab.isc.org/isc-projects/bind9/-/issues/2982

st 27. 10. 2021 o 11:53 Blažej Krajňák <blazej.krajnak at gmail.com> napísal(a):
>
> Hello,
>
> few days ago I updated our recursive resolvers at AS50242 from Debian
> 10 to 11 to be able to enable stale-answer afer Facebook incident.
> However, today I got bug reports from customers. Their browser often
> fail at page loading with DNS_PROBE_FINISHED_NXDOMAIN. After few
> seconds (and after browser DNS re-query) page will load correctly. In
> Bind9 log I see many of messages like:
>
> Oct 27 11:34:13 srv-snv-production named[576109]:
> configuration.ls.apple.com resolver failure, stale answer unavailable
> Oct 27 11:34:13 srv-snv-production named[576109]: client
> @0x7fc71806cd58 10.202.42.196#58876 (configuration.ls.apple.com): view
> clients: query failed (SERVFAIL) for
> configuration.ls.apple.com/IN/TYPE65 at query.c:5832
> Oct 27 11:34:13 srv-snv-production named[576109]:
> configuration.ls.apple.com resolver failure, stale answer unavailable
> Oct 27 11:34:13 srv-snv-production named[576109]: client
> @0x7fc7180715a8 10.202.42.196#49219 (configuration.ls.apple.com): view
> clients: query failed (SERVFAIL) for configuration.ls.apple.com/IN/A
> at query.c:5832
>
> After I turned off stale-answer, problem looks to be resolved. I'm
> attaching huge debug log of above failures - hope somebody will find
> problem from this. The problematic query starts at 27-Oct-2021
> 11:34:13.858
>
> https://drive.google.com/file/d/1qiyLa8CfNN54PUktth6R4kT8PpohNsde/view?usp=sharing
>
> Linux srv-le-production 5.10.0-9-amd64 #1 SMP Debian 5.10.70-1
> (2021-09-30) x86_64 GNU/Linux
> bind9/stable,now 1:9.16.15-1 amd64
>
>
> Regards,
> Blažej Krajňák