[CentOS] DNS lookup delay with centos & postfix
Steve Lindemann
steve at marmot.org
Wed Jul 25 21:47:55 UTC 2012
On 7/25/2012 3:21 PM, Tom Brown wrote:
> Does dig use libresolv or read directly from resolv.conf? Also do you have a timeout configured in resolv.conf or are you relying on the os default?
dig uses resolv.conf and no timeouts are configured there. I don't know
there the OS would have a default configured or what it is. Another
reply indicated there would be a 5 second delay. That seems a bit high
to me.
I used dig from the email svr command line with the primary DNS svr up
and (naturally) it pulled from there as normal. Then I downed the
primary DNS svr, saw the nagios check fail and tried again. The same
dig lookup was actually faster and pulled from the secondary DNS svr
just fine. And, again, the nagios alert cleared as soon as the primary
DNS svr was back online.
For both tests I used: dig mx google.com
--
Steve
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