| Re: [chrony-users] Repeated 'refresh'es may cause excessive DNS queries |
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- To: chrony-users@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-users] Repeated 'refresh'es may cause excessive DNS queries
- From: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
- Date: Tue, 12 Mar 2024 17:02:34 +0100
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On Tue, Mar 12, 2024 at 04:35:59PM +0100, t.barnewski@xxxxxx wrote:
> STEPS TO REPRODUCE:
> 1) Install a DNS server on machine A (can also be a VM) and configure it to
> always reply with a TTL of 0 for certain domains. This can be accomplished with
> dnsmasq and a hardcoded entry in /etc/hosts for, say, 2.europe.pool.ntp.org:
>
> > cat /etc/hosts
> # HACK for testing: use ptbtime1.ptb.de as source
> 192.53.103.108 2.europe.pool.ntp.org
> [snip]
>
> 2) On machine B, point the local DNS resolver to machine A.
> Install chrony and configure it to use only the source from step 1.
>
> > cat /etc/chrony/chrony.conf
> pool 2.europe.pool.ntp.org minpoll 10 iburst
> [snip]
>
> 3) Repeatedly issue "chronyc refresh" commands on machine B and watch the sparks
> (and the DNS queries) fly.
That seems to be working for me as expected. I see one request per
refresh. Can you please build chronyd with --enable-debug and post the
chronyd -dd output for first few refresh commands?
--
Miroslav Lichvar
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