Can someone explain how DNS synthetic extension works in background. Synthetic monitor DNS monitoring & observability | Dynatrace Hub
What exactly it checks and what network connectivity is required from AG server to DNS server. Do we need connectivity on any specific port?
Have not used it, bust certainly you should need connectivity on port 53, for UDP traffic. It will make UDP/53 requests and give you performance & availability metrics.
Don't forget that you already have DNS metrics with OneAGent, for every server being measured. Check out Data Explorer for DNS metrics, as they really represent the real DNS traffic going on in your servers.