BIG-IP DNS monitor

I'm simplifying here a bit, but in general, it is best to let BIG-IP LTM monitor its resources and then use iQuery to communicate virtual server status to BIG-IP DNS systems. It does not matter if you add the virtual server to the BIG-IP DNS system manually or using auto discovery. If the virtual server is being monitored on the BIG-IP LTM system (through its pool members), then it is not necessary to have additional monitors defined on the virtual server on BIG-IP DNS - especially if the monitor tests are essentially the same on both BIG-IP DNS and BIG-IP LTM, such as might be the case with an HTTP monitor.