topic Re: Request to unmonitored hosts in Open Q&A

Request to unmonitored hosts

Swabh — Wed, 04 Sep 2024 09:02:30 GMT

Hi , Can someone help me understand how is "Request to unmonitored hosts" detected? Is it basis on the code or does oneagent monitor outgoing calls?

I have oneagent running on webservers only. I have not instrumented the appserver. As per my observation the calls from webserver to appserver will not be detected.

But my client needs a reason why the calls from webserver to appserver not being captured as ' request to unmonitored hosts'.

Thanks in advance!

Swabh

Re: Request to unmonitored hosts

AntonioSousa — Wed, 04 Sep 2024 09:39:18 GMT

@Swabh, In most most cases, I would say they are detected when Dynatrace instruments an application/service, in Full-Stack mode, and then tracks outgoing calls from those applications. In the case where that request doesn't have a corresponding trace/purepath from the side receiving the request, that is considered a "Request to unmonitored hosts" .

There are lots of associated details. For one, you should consider the differences between "Request to unmonitored hosts" and "Requests to public networks". For this latter one:

https://docs.dynatrace.com/docs/platform-modules/applications-and-microservices/services/service-monitoring-settings/monitor-3rd-party-services

Also, there are "opaque services":

https://docs.dynatrace.com/docs/platform-modules/applications-and-microservices/services/service-detection-and-naming/service-types/opaque-services

And it's also possible that HTTP headers are being lost, and that typically cuts the association between both traces, creating "Request to unmonitored hosts" on the calling side.

Re: Request to unmonitored hosts

Theodore_x86 — Mon, 25 Aug 2025 14:34:08 GMT

Hello @AntonioSousa.

What is the difference between unmonitored hosts and Opaque services? To my understaning they both receive requests from monitored hosts but outgoing calls cannot be tracked because instrumentation is missing.

Re: Request to unmonitored hosts

AntonioSousa — Mon, 25 Aug 2025 15:16:59 GMT

@Theodore_x86

On the calling side, when OneAgent sees a call going out from a client to a server, but doesn't receive it on the other side (server side), because there is no OneAGent running on that server, it's a "Request to unmonitored hosts" or "Requests to public networks".

If the same call is made to a server that has OneAgent running, but OneAgent was unable to instrument the process for whatever reasons, an "Opaque service" is created. The links above explain it in quite detail.

Re: Request to unmonitored hosts

Theodore_x86 — Wed, 27 Aug 2025 09:31:03 GMT

Hello @AntonioSousa

Unmonitored hosts concept is clear.

Opaque services though, I was curious about how Dynatrace understands that a call, which is not received by an instrumented app, is targeted to a Node with OneAgent nevertheless...I guess that targeted hostname after resolved is correlated with "Nodes with Agent installed" names.

Re: Request to unmonitored hosts

AntonioSousa — Wed, 27 Aug 2025 10:57:06 GMT

@Theodore_x86 ,

The details of how Dynatrace does it are many times not known. It sees the requests going out on server A, to a server B that Dynatrace knows it has an agent. On server B, it knows which process is listening on each port, has network monitoring, and as such knows it has to be a service of that process. But, once it was unable to instrument that process, an "opaque service" is so created. Once again, this is my interpretation on how it's done 😊