DNS resolver

TL;DR. Point your devices at Quad9 (9.9.9.9) over DNS-over-HTTPS. Swiss non-profit, no commercial logging, blocks known-malicious domains by default. One toggle, nothing to pay, immediate upgrade over whatever your ISP gives you. NextDNS if you want a dashboard, self-host AdGuard Home if you want nobody else in the loop at all.

What this category protects

Every domain you load resolves through DNS before the first byte of a page arrives. Your ISP’s resolver sees that list in the clear — timestamps, every subdomain, every tracking beacon. That log is sold, subpoenaed, and in some jurisdictions mandated. The same list also leaks through every “encrypted” channel if the resolver is unencrypted: see the DNS leaks vector for the full picture of how a VPN-plus-bad-DNS combo is still a leak.

Picking a specific resolver and encrypting the queries (DoH or DoT) closes the biggest outstanding network-level leak after the tunnel itself. It also moves the trust boundary from “whoever my ISP contracts with” to an operator you picked on purpose.

This just works: Quad9

9.9.9.9 and 2620:fe::fe. Operated by the Quad9 Foundation, a Swiss non-profit funded by grants — not ad revenue, not malware-SaaS dashboards. No commercial query logging; the only retention is aggregate counters for capacity planning and real-time abuse detection, flushed continuously. DNS-over-HTTPS endpoint: https://dns.quad9.net/dns-query. DoT endpoint on port 853. Malware-domain filter is on by default using feeds from 19 threat-intel partners.

Set it in the OS (Windows 11 Network settings, macOS Network, Android Private DNS dns.quad9.net, iOS DoH profile). Set it in your browser (Firefox → DoH → custom, Brave → privacy → secure DNS). Set it on your router and it covers every device on the LAN. What you give up: nothing meaningful for home use. Power users sometimes want more granular block-list control; for that, NextDNS.

Alternatives

• Cloudflare 1.1.1.1 — fastest DNS on the planet in most benchmarks, audited no-logging policy (KPMG annual). The worry is concentration — Cloudflare is already a CDN giant seeing half the web; handing them your DNS too concentrates more signal with one vendor. Fine choice, different threat model.
• NextDNS — DNS-as-a-service with a dashboard. Free tier covers 300k queries/month (plenty for a phone or small household); $2/month Pro unlocks unlimited. Per-device profiles, custom block lists (supports every major blocklist feed), and logs-optional. Run by a two-person French team.
• AdGuard Home (self-hosted) — run your own resolver on a Raspberry Pi or NAS. DoH/DoT front-end, dnsmasq or AdGuard-native back-end, your own block lists. No third party sees your query list at all. Requires upkeep, a basic Linux footprint, and the discipline to keep the thing patched.
• Mullvad DNS — if you use Mullvad VPN, their resolver ships free at base.dns.mullvad.net. Four content-filter flavours (adblock, family, all). Works outside the tunnel too.

Comparison matrix

Resolver	DoH	DoT	Filtering	Logs policy	Anycast	Price
Quad9	Yes	Yes	Malware (default)	Aggregate only, real-time flush	Yes	Free
Cloudflare 1.1.1.1	Yes	Yes	Optional via 1.1.1.2 / 1.1.1.3	Audited no-logs	Yes	Free
NextDNS	Yes	Yes	Custom, per-profile	Off / 1h / 1d / forever (your choice)	Yes	Free or $2/mo
AdGuard Home (self-host)	Yes	Yes	Custom, your lists	You decide	No (your IP)	$0 + hardware
Mullvad DNS	Yes	Yes	4 flavours	No-logs	Yes	Free (no account needed)

Common mistakes

• Setting a private resolver in the browser only. Every other app on the device (Steam, system updaters, Slack, notification services) still uses the OS resolver. Set it OS-wide.
• Skipping IPv6. If the OS reaches out via IPv6 first and your v6 DNS is still the ISP default, half your queries leak. Set both 9.9.9.9 and 2620:fe::fe.
• Trusting the router to honour DHCP option 6. Many smart-home devices hardcode 8.8.8.8 and ignore what the DHCP server hands them. Blackhole outbound port 53 on the router and force everything through your resolver.
• Using a filtered resolver and blaming broken sites on the VPN. A strict family or malware filter will NXDOMAIN things you want. When something breaks, bypass the filter first, VPN second.
• Running DoH but leaving Disable-IPv6-privacy-extensions on. Your v6 suffix is still a stable device ID even through a clean resolver.

Setup

DNS-over-HTTPS setup guide walks through OS, browser, and router. For self-hosting the recursive-with-blocking path, see Pi-hole setup — AdGuard Home is similar in spirit, swap the install step.

Related categories

• VPN — tunnels the traffic; DNS decides who sees the domain list.
• Router-level VPN — stack the resolver and the tunnel on the LAN edge.