> 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 i would always have a timeout in your resolv.conf rather than relying on the OS default. Set that to 1 second and test again to see if there is any difference.