What defines an external service in Dynatrace?

An external service in Dynatrace is defined as any service that is called but not directly monitored by Dynatrace OneAgent. This typically includes services that are running outside of the environment where Dynatrace is installed. These could be APIs, microservices, or any other services that your application may depend on and that do not have Dynatrace agents installed to monitor them directly.

By identifying external services, Dynatrace helps users understand how their applications interact with these services and assess the performance and reliability of these interactions. Recognizing external services is crucial because it allows teams to troubleshoot and optimize the performance of their applications comprehensively, including both the internal and external components that impact the overall user experience.

The other options describe different scenarios that do not align with the definition of an external service in Dynatrace. For instance, an internally monitored service or a service interacting directly with a database would have data gathering capabilities through the OneAgent, which means they would not qualify as external services. A third-party application could be an external service if it meets the criteria of being called but not monitored, but the defining factor is whether it is directly monitored by Dynatrace OneAgent, which narrows it down to the specific definition in option B.