Quad9

Quad9 is a free public DNS resolver run by the Quad9 Foundation, a Swiss public-benefit foundation headquartered in Zürich. The service moved its headquarters from California to Switzerland in 2021. Devices, routers or browsers send their lookups to 9.9.9.9 instead of the internet provider's resolver, and Quad9 refuses to resolve domains that are known to distribute malware or run phishing.

Features

• Recommended setting on 9.9.9.9 with malware and phishing blocking and DNSSEC validation, plus a variant with EDNS client subnet (9.9.9.11) and an unfiltered variant (9.9.9.10)
• Block lists compiled from more than 20 threat intelligence partners; every blocked domain can be looked up on the website together with the source of the block
• Encrypted lookups via DNS over HTTPS, DNS over TLS and DNSCrypt, over IPv4 and IPv6
• More than 230 resolver clusters in over 110 countries, according to Quad9
• Quad9 Connect, an Android app available on F-Droid

Privacy and limits

According to its policy, Quad9 does not record client IP addresses and keeps only aggregate counters. There are no accounts, so there are also no personal block lists or query statistics. The filter can block a legitimate site in rare cases; a form on the website handles false positives, and the unfiltered address is the fallback. Anyone who wants to block ads and trackers as well needs a different service, for example AdGuard DNS.