In this paper we present Netalyzr, a network measurement and debugging service that evaluates the functionality provided by people’s Internet connectivity. The design aims to prove both comprehensive in terms of the properties we measure and easy to employ and understand for users with little technical background. We structure Netalyzr as a signed Java applet (which users access via their Web browser) that communicates with a suite of measurement-specific servers. Traffic between the two then probes for a diverse set of network properties, including outbound port filtering, hidden in-network HTTP caches, DNS manipulations, NAT behavior, path MTU issues, IPv6 support, and access-modem buffer capacity. In addition to reporting results to the user, Netalyzr also forms the foundation for an extensive measurement of edge-network properties. To this end, along with describing Netalyzr’s architecture and system implementation, we present a detailed study of 130,000 measurement sessions that the service has recorded between June 2009 and September 2010.
(This paper was published at Internet Measurement Conference 2010. The authors are Christian Kreibich, Nicholas Weaver, Boris Nechaev and Vern Paxson)