[Dnsmasq-discuss] Logging milliseconds//Addendum

[mabra at manfbraun.de]

Hi !

Many thanks for your investigation !!!

I'll not bother you or anyone in any way, but we may just have
different perspectives to see the problem. I just tell my
opinion about the log - noone should start to patch something.
I am also the type, which waits for distro updates ... to shy to
install from source.

My log-example was mainly to show, that DNSMasq COULD
give a better help through it logs - it was not thought to
explain the problem. That, what you asked to me, exactly
that - so I think - should answer the log ... pobably, one day.

I think, I have good control over my environment and I ensure,
if I make tests like my DNS tests, that the line is not loaded !
The log-example stems just from real-live, were countless apps
are running and different computer are up.  There is, for example,
a RSS reader, which starts batch-loads for a big list of websites - just
to explain, why I do not wonder about the logfile. There is much
more, like over 20 Virusprotection solution, which updates every
hour ...

So I'll start to make a tool, which systematically answers some
(all known open/free DNS in Germany) and measure the overall
response. Will need some time, so. In the meantime, I am using
the DNS from the ISP - anyway what may cause the problem,
if I use the DNS from ISP, I never have problems at all ..... !!!

If this would not be the case, I really would also suspect
DNSMasq (indirectly), because this runs on a stonehenge
old box, with really no memory free .... I see in my syslog,
the Nagios command sometimes fail, due to not enough
memory. This cannot be fixed very fast - too many thing
on my list. But a new firewall machine is already on the
table ...

Thanks again and my best regards,
Manfred

[I hope, this "reply all" will not cause another thread ...]


> -----Original Message-----
> From: Albert ARIBAUD [mailto:albert.aribaud at free.fr]
> Sent: Tuesday, June 21, 2016 8:05 PM
> To: mabra at manfbraun.de
> Cc: dnsmasq-discuss at lists.thekelleys.org.uk
> Subject: Re: [Dnsmasq-discuss] Logging milliseconds//Addendum
> 
> Hi Manfred,
> 
> Le Tue, 21 Jun 2016 17:30:13 +0200
> <mabra at manfbraun.de> a écrit:
> 
> > Hi All !
> >
> > I just changed some free DNS against some other free DNS
> > and now, I have more problems then bevore. Though I'll
> > extend my logging thoughs: In the DNSMasq answer is not
> > visible which of dns provided the answer - that makes diag
> > problematic.
> 
> Seems you started a new thread while I was answering on the previous
> one.
> 
> Short answer: I would suggest that you avoid trying "this and that" as
> well as ad hoc patching", and that you follow a more systematic approach
> to solving your problem, by running tcpdump on the machine which hosts
> your dnsmasq.
> 
> Also, you should really try and make other hypotheses than just your ISP
> messing with DNS. For instance, have you tried to find out how much of
> your uplink bandwidth you're using? Because if your uplink saturates,
> then UDP packets sch as DNS requests might get dropped by your ISP's
> modem.
> 
> > Thanks anyway,
> > Manfred
> 
> Amicalement,
> --
> Albert.