[Xymon] DNS test timeout for a downed DNS server.

[Henrik Størner]

On 24-07-2012 22:17, Steve Holmes wrote:
> Xymon 4.2.3. One of the DNS servers we monitor was down. The bbtest
> total time went from under 30 seconds to over 900 seconds almost all
> of which was for the DNS test.
>
> This caused a number of problems. I removed the dns tag from the down
> server and the time dropped back to the normal level.
>
> The mysteries to me are why did Xymon continue to test the DNS service
> on that server while the conn test was red? Why did it
> take 900 seconds for it to time out, even though I was running with
> --dns-timeout=60?

DNS timeout handling does not work correctly in versions prior to 4.3.8, 
it is a case of the DNS library (c-ares) not behaving the way I thought 
it did.

4.3.8+ has a workaround in place so the timeout is fixed at 
approximately 25 seconds. You can achieve almost the same result by 
running the old bbtest-net utility with "--dns-timeout=2" (no, this 
won't cause DNS lookups to timeout after 2 seconds).


> And more importantly, is the behavior still the same in 4.3.9?

No.


Regards,
Henrik