I have a DNS lookup which executes every 5 minutes across 6 servers to check that the server can resolve its own hostname (i.e. DNS recursion is working.)
One of these servers decides to spontaneously return an UNKNOWN value for this check - about once a day on average. What's worse, is it doesn't notify me when this happens so it's impossible to be able to check whether it's a false alarm.
In the agent log of the server, I see this - and the time does correlate to these UNKNOWN values.
What's strange is that 5 or 10 minutes later, the check starts working again without any intervention - so how can it be "not supported"?
One of these servers decides to spontaneously return an UNKNOWN value for this check - about once a day on average. What's worse, is it doesn't notify me when this happens so it's impossible to be able to check whether it's a false alarm.
In the agent log of the server, I see this - and the time does correlate to these UNKNOWN values.
8376:20100222:104025.251 Active check [net.tcp.dns.query[89.200.138.130, grafton.networkmail.eu, A]] is not supported. Disabled.