Identification of traffic flows hiding behind TCP port 80

Beyond Quality of Service and billing, one of the most important applications of traffic identification is in the field of network security. Despite their simplicity, current approaches based on port numbers are highly unreliable. This paper proposes an identification approach, based on a cascade of decision trees. The approach uses the sign pattern and payload size of the first four packets in each flow, thus remaining applicable to encrypted traffic too. The effectiveness of the proposed approach is evaluated on five real traffic traces collected in different time periods and over four different networks. The obtained overall accuracy gives us grounds to consider the adoption of this approach as stand-alone in on-line platforms for network traffic identification or in combination with classical firewall architectures.