Application detection rules are evaluated by OneAgent on the first instrumented tier of your application. See How does Dynatrace apply your application detection rules? for more details.
In some cases, an uninstrumented component, such as a reverse proxy or a load balancer, is between the browser and the first instrumented tier of your application and rewrites the URL. As a result, the URL used for application detection differs from the URL that was originally requested by the browser.
In this scenario, we cannot use the URL we see in the web browser and test it in the detection rules checker (Settings -> Web and mobile monitoring -> Application detection). Instead, we have to find the related server-side URL that is available in Trace / PurePath, under Host and URI fields.
Below is short video showing how to easily find the Host and URI field values from Trace / PurePath that are associated with the default My web application:
Note: If you find in Trace / PurePath other fields with domains (i.e. X-Forwarded-For), check the Settings -> Web and mobile monitoring -> Host name determination configuration, since the order matters and other field values might be taken into consideration.
