Beyond Ad Hoc: A Generalized Framework for Middlebox Detection

As Internet middleboxes become increasingly prevalent, their influence on traffic streams introduces both significant challenges and opportunities for network management. Enabling end hosts to detect these middleboxes is not only beneficial but, in many cases, crucial. Existing detection approaches are typically ad hoc, designed to target a specific middlebox type. In contrast, we propose a generalized framework capable of detecting a broad range of middleboxes. To illustrate this concept, we use transparent middleboxes as an example—middleboxes that interfere with traffic without altering its contents, while maintaining the appearance of simple routing and forwarding. This transparency property makes end‐to‐end detection of such middleboxes particularly challenging. In this paper, we present a generalized framework for detecting transparent middleboxes. Using this framework, we detect three common types of middleboxes: network compression, traffic prioritization, and traffic shaping. Our results are validated through analysis, network simulations, and live Internet experiments involving real middleboxes.