[Pdns-users] Intermittent recursion failure due to timeout

[Brian T]

Brian and Bert - thank you both for the analysis and sanity check.  I'll
continue to focus on the network between me and the affected name server.

On Tue, Jan 23, 2018 at 2:28 PM, bert hubert <bert.hubert at powerdns.com>
wrote:

> Hi Brian,
>
> On Tue, Jan 23, 2018 at 02:00:58PM -0700, Brian T wrote:
> > My recursor config has 'network-timeout' set to 5500ms (instead of the
> > default 1500ms), so I can understand the "timeout resolving after
> > 5535.35msec" message, but I was surprised by the timestamps of the
> messages
> > all being the same.  Are these messages flushed to syslog all at once or
> is
> > the timeout really happening immediately?
>
> This is exactly why we note the 'observed' time passed in the log line.
> When running with trace=servfail, we indeed buffer the log with one single
> timestamp.
>
> > leading up to the timeout that look suspicious?  This has been happening
> > about 10-15 times per day and started happening on Jan 18th.  I see
> similar
> > timeouts to 3 other sites, but this one most frequently.
>
> 91.189.95.68 is the host causing timeouts.  It answers very reliably for me
> from here, but it is close to me (London).  It may be that this address
> isn't very well served to you somehow.
>
> > Lastly, is there any way to retry here?  I'd rather lower the network
> > timeout and attempt a retry if possible.
>
> "Jan 23 05:47:55 n422 pdns_recursor[8739]: [414333]
> nova.clouds.archive.ubuntu.com: Cache consultations done, have 1 NS to
> contact"
>
> Usually domains have at least two nameservers.  That generates two
> attempts,
> which should really be enough.
>
> For domains with only a single nameserver with a single IP address, we
> might
> indeed consider trying twice. But there is no way to make that happen right
> now from the configuration.
>
> For now, I think you are mostly observing a somewhat unreliably hosted
> domain name.
>
>         Bert
>



-- 
Brian Talley
b225ccc at gmail.com ::: (720) 6 <https://www.google.com/voice/#phones>36-0004
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