Let's look at each of these configurations in detail.
As an example, a page serves all devices the same HTML which includes a
to include a smartphone-optimized image or ad code instead of the
Given that the server returns different HTML to different user-agents, combined detection is considered a type of dynamic serving configuration. The details are described in full here, but to briefly summarize them, the website should include the "Vary: User-agent" HTTP response header when a URL that serves different HTML content to different user-agents is requested.
In this configuration, all devices are served the same HTML which includes a
different content depending on the requesting user-agent. That is, the