Public DNS Servers
What a Public DNS Server Does
Public DNS servers are recursive resolvers that anyone can use, not only the customers of one internet provider. A recursive resolver does the lookup work for your device: it queries the DNS hierarchy on your behalf, caches the answer and returns it. For background on this role, see recursive and authoritative servers.
Well-known examples include 1.1.1.1, run by Cloudflare, 8.8.8.8, run by Google, and 9.9.9.9, run by Quad9. These are named only as examples of the concept, not as recommendations.
How They Differ From Your Provider’s Resolver
Most home connections use the resolver supplied by the internet provider by default. Public services differ from it in a few main areas:
- Privacy: each operator has its own logging and retention policy. The choice is mainly about trust in that operator.
- Filtering: some services block known malware or phishing domains, and some offer family filters. Others answer every query without filtering.
- Speed: many large services run anycast networks in many locations, which can answer quickly. Actual speed depends on where you are and on what is already cached, so results vary.
- Validation: many services check DNSSEC signatures, but not all do, so it is worth checking each service’s documentation.
When a Public Resolver Can Cause Problems
Changing resolvers changes the answers you see, so a few situations are worth knowing about:
- Private names: internal hostnames, such as a company intranet or a router’s local name, stop resolving, because a public resolver cannot see private zones.
- Location-based answers: some large services return different servers depending on where the lookup appears to come from. Some public resolvers pass a rough location hint, part of your network prefix known as EDNS Client Subnet, while others do not, so you may reach a different server.
- Network filters: parental controls or filters set on a router can be bypassed when devices use another resolver.
Frequently asked questions
Are public DNS servers faster than my provider’s?
Not always. Public services use large caches and distributed networks, which can help, but speed depends on your location, the network path and whether the record is already cached. A provider’s resolver may be closer to you and respond quickly. Test rather than assume, and treat any single benchmark as a snapshot.
Do public DNS servers keep logs of my queries?
It depends on the service. Each provider publishes its own policy describing what it stores, for how long and whether it shares data. Your internet provider can still see plain DNS traffic from your connection unless the queries are encrypted, so the real question is which operator you trust with that information. Read the current policy before you choose. For encrypted options, see encrypted DNS.