Quad9

Quad9 is a free public DNS service operated by the Quad9 Foundation, a not-for-profit foundation based in Zurich, Switzerland. DNS is the step that turns a domain name into a network address, and Quad9 replaces the resolver a device would otherwise get from its internet provider or employer, adding a security check at that step. Its site names the Global Cyber Alliance, IBM and Packet Clearing House as the organisations behind its founding.

What the service does

Each lookup sent to Quad9's recommended addresses, 9.9.9.9 and 149.112.112.112 with their IPv6 equivalents, is checked against lists of domains known to host malware, phishing, spyware or botnet infrastructure, and a match is refused so the device never connects. The lists come from about twenty commercial and public threat intelligence partners; Quad9 distributes their data rather than producing its own indicators, and it blocks security threats only, not content, advertising or trackers. DNSSEC validation runs on all addresses. A second address set adds EDNS client subnet support and a third resolves without any blocking. Encrypted DNS over HTTPS and over TLS is supported.

The resolvers are anycast and sit mostly at internet exchange points; the site reports more than 230 resolver locations in over 110 countries and an average of more than 670 million blocked lookups a day.

Who it serves

Households, small organisations, enterprises and network operators that want a no-cost first layer of protection that works on almost any connected device, including equipment where security software cannot be installed. Quad9 says it does not log users' IP addresses in normal operation and was designed for GDPR compliance, and it is funded by sponsors and donations rather than by selling data.

Key facts

Legal form: Swiss not-for-profit foundation, governed by a Foundation Council Address: c/o SWITCH, Werdstrasse 2, 8004 Zurich, Switzerland Chair of the council: Bill Woodcock General manager: John Todd Price: free