Maintained by: NLnet Labs

[Unbound-users] forward servers: option to log failed requests

Felix Schueren
Mon Aug 31 10:22:08 CEST 2009


Hello,

we're still tracking a "some miniscule amount of queries fail every 
couple of days" case with unbound, and we think it might be related to 
unbounds backoff timer. Dumping unbound-control lookup (forwarded-zone) 
every minute yielded this:

normally looks like
(forward server 1)          rtt 27 msec, 0 lost. EDNS 0 probed.
(forward server 2)          rtt 23 msec, 0 lost. EDNS 0 probed.


problem timeframe:

Mon Aug 31 00:47:09 CEST 2009
(forward server 1)          rtt 800 msec, 1 lost. EDNS 0 probed.
(forward server 2)          rtt 31 msec, 0 lost. EDNS 0 probed.
--
Mon Aug 31 00:48:09 CEST 2009
(forward server 1)          rtt 800 msec, 1 lost. EDNS 0 probed.
(forward server 2)          rtt 27 msec, 0 lost. EDNS 0 probed.
--
Mon Aug 31 00:49:09 CEST 2009
(forward server 1)          rtt 800 msec, 1 lost. EDNS 0 probed.
(forward server 2)          rtt 27 msec, 0 lost. EDNS 0 probed.
--
Mon Aug 31 00:50:09 CEST 2009
(forward server 1)          rtt 800 msec, 1 lost. EDNS 0 probed.
(forward server 2)          rtt 27 msec, 0 lost. EDNS 0 probed.
--
Mon Aug 31 00:51:09 CEST 2009
(forward server 1)          rtt 800 msec, 1 lost. EDNS 0 probed.
(forward server 2)          rtt 27 msec, 0 lost. EDNS 0 probed.

and we had a couple of dns-related error messages ("unable to resolve") 
for queries that I know go to the forward servers at 00:50:03 +0200 that 
day.

As the volume is too large to dump properly, I would like an option per 
forward server or per forward zone to dump failed requests with the full 
query. These forward servers should _always_ answer, each failed query 
should be logged in a configurable verbosity level (so we could set it 
to 1 - 2 is pretty much unusable due to the high volume). Even if you 
would not want it in mainline, maybe a debug build would be possible?


Thoughts?

Kind regards,

Felix

-- 
Felix Schüren
Head of Network

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