Global Detection Of DNS-Layer Disruption


Satellite is a tool to detect DNS interference remotely, scalably, ethically, and globally.

We begin by identifying open DNS resolvers in the IPv4 space and filtering it to rigorous ethical standards, utilizing only about 10,000 of 10,000,000 resolvers (0.1%) spanning 170 countries. We use the latest Alexa top 1K and Citizen Lab global test list as our input domains, and query every resolver with every domain. Using multiple heuristics to avoid false positives, such as AS number, AS name, and HTTP static content hash we compare with answers from designated control resolvers to determine the occurrence of interference. Furthermore, to confirm censorship, we visit the pages hosted on answer IPs to check for presence of a blockpage.


All the data collected from the Observatory is publicly available, including metadata.


Satellite was presented at the 2016 USENIX Annual Technical Conference, and was awarded best student paper. The paper covers the design of the measurement system, and the ability for the bipartite graph of IPs and domains to reveal CDN infrastructure. This tool is made after Iris, presented at USENIX 2017, and Satellite.

August 2017 USENIX Security

Global Measurement of DNS Manipulation

Paul Pearce Ben Jones Frank Li Roya Ensafi Nick Feamster Nick Weaver Vern Paxson

PDF Talk Slides

title={Global Measurement of DNS Manipulation},
author={Paul Pearce and Ben Jones and Frank Li and Roya Ensafi and Nick Feamster and Nick Weaver and Vern Paxson},
booktitle={USENIX Security},

June 2016 USENIX Annual Technical Conference

Satellite: Joint Analysis of CDNs and Network-Level Interference

Will Scott Thomas Anderson Tadayoshi Kohno Arvind Krishnamurthy

PDF Talk Slides

title={Satellite: Joint Analysis of CDNs and Network-Level Interference},
author={Will Scott and Thomas Anderson and Tadayoshi Kohno and Arvind Krishnamurthy},
booktitle={USENIX Annual Technical Conference},


Satellite for Censored Planet is developed and maintained by Ram Sundara Raman, Elisa Tsai, Apurva Virkud,and Roya Ensafi.

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