Quad9 Public DNS Resolver Service

Quad9 is a free, anycast recursive domain name system (DNS) service that provides robust security for internet users by blocking malicious domains. Launched in August 2017, the Quad9 project was initially founded through a collaborative effort involving Packet Clearing House, Global Cyber Alliance, and IBM. The service is operated by the Quad9 Foundation, a non-profit organization headquartered in Zurich, Switzerland, while maintaining significant operational infrastructure in the United States and globally. Quad9 focuses on privacy and security, refusing to sell user data or bundle browsing analytics, distinguishing itself through its threat-intelligence-driven blocking capabilities.