[Podcast] Quad 9 — Measurement in the privacy-preserving public DNS service

In this episode of PING, we hear from Darren Kara, a Principal Engineer at Quad9.

If you haven't heard of Quad9, it is one of the longest-running public Domain Name System (DNS) services, with a history stretching back more than 10 years. It began as an initiative involving Packet Clearing House (PCH), IBM, the Global Cyber Alliance (GCA), and SWITCH Telecom in Switzerland. Quad9 now operates as a public-benefit, not-for-profit foundation headquartered in Switzerland

Among public DNS services from providers such as Google and Cloudflare, Quad9 stands out in two areas: Protecting user privacy and protecting users from malware and phishing.

The first goal gives Quad9 a very different approach to measurement. In other measurement environments, packet samples or complete captures, such as those used for DNS-OARC's Day in the Life of the Internet (DITL) collection, may be available for analysis. At Quad9, information that could identify an individual user does not leave the location where it is collected. Instead, Quad9 uses aggregate data and anonymizes source addresses.

The second goal, protecting users from malicious destinations, relies on collaboration with threat intelligence providers around the world. Quad9 uses these threat intelligence feeds to prevent DNS queries from directing users to known malicious destinations. It can also provide information back to threat intelligence providers to help them refine their signals and better understand risks in different parts of the world.

This process also requires careful anonymization. Quad9 must ensure end-user information doesn't leak and that intelligence from one provider isn't exposed to another.

Darren Kara discusses Quad9's architecture and how the service approaches management and measurement. He is also keen to hear from threat intelligence organizations in the Asia Pacific region to improve collaboration and coverage for the wider community. Interested organizations can get in touch through the Quad 9 contact page.

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