Maintained by: NLnet Labs

[Unbound-users] Unbound stops answering after ADSL-line bounce

W.C.A. Wijngaards
Mon Jan 23 09:21:08 CET 2012


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Hi Jan-Piet,

Yes it marks servers as down and stops sending queries.  There was a
rewrite for better handling of this case, if you run an older version
an update may be useful.  However, all versions step down packets to
hosts that are down.

This has a timeout of x minutes (1-15).  After that your service
should re-enable again.  If the downtime was under two minutes, you
have to wait that amount of time for service to resume (exponential
backoff used here).  If the downtime was longer, you may have to wait
15 minutes (infra-ttl config option) before service resumes to hosts
that were probed to be 'down'.

If you want service to instantly go down and up with the line
downtime, and you can notice the line-bounce via some other method,
then you could use e.g. unbound-control flush_infra to resume traffic.

Best regards,
   Wouter

On 01/23/2012 08:29 AM, Jan-Piet Mens wrote:
> Hello,
> 
> I'm running unbound-1.4.14 behind an ADSL line which is cycled once
> in a while. This can take anything from several seconds to
> four/five minutes (router reboot) before the Internet is visible
> again. At this point, I've been experiencing Unbound replies with a
> SERVFAIL to all queries, as though it marks the DNS servers as
> being down and stops sending requests to them.
> 
> Is this a known issue?
> 
> (Somebody else has also experienced this problem with a vanilla
> Unbound on what I call DAP [1], and he's reported this to me
> privately with a pcap and verbosiyt=5 logfile I can submit
> privately if required.)
> 
> Regards,
> 
> -JP
> 
> [1]: http://jpmens.net/pages/dns/dnssec-appliance/ 
> _______________________________________________ Unbound-users
> mailing list Unbound-users at unbound.net 
> http://unbound.nlnetlabs.nl/mailman/listinfo/unbound-users

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