Which DNS providers have undergone independent audits or transparency reports for their no-logs claims?
Executive summary
A handful of public DNS services have subjected their privacy promises to external scrutiny: Cloudflare explicitly commissions annual KPMG audits and publishes reports about its “no-logging” handling of querying IP addresses [1], while Quad9 emphasizes transparency and a privacy-first governance model though its materials focus more on policy and architecture than a named recurring third‑party audit in the provided reporting [2]. Several other resolvers — including NextDNS, Mullvad’s DNS offering, and major operators such as Google/OpenDNS — appear in the literature with specific logging practices or transparency reports, but publicly verifiable independent audit evidence is uneven or not cited in the available sources [3] [2] [4].
1. Cloudflare: the clearest external audit trail
Cloudflare’s public resolver (1.1.1.1) states it commits not to write querying IP addresses to disk and to delete short-lived logs within 24 hours, and TechRadar reports Cloudflare has retained KPMG to audit those practices annually and to produce a public report confirming its promises [1].
2. Quad9: transparency and governance, but audit language is different
Quad9’s public materials stress a privacy-first mission, a multi-stakeholder foundation, relocation to Switzerland for GDPR protections, and an explicit “we don’t log IPs” posture, making it one of the more transparent DNS projects in policy and governance terms; the reporting shows strong self-stated transparency but does not cite a named annual third‑party audit in the provided snippets [2].
3. NextDNS, Mullvad DNS and others: mixed signals and product-level transparency
PrivacyGuides and other DNS guides note NextDNS’s operational nuances (free‑plan limitations, account data retention for premium profiles) and Mullvad’s explicit no-logs claim for its DNS service, indicating strong privacy claims at the product level, but the sources do not provide a clear, single-line citation showing independent, recurring third‑party audits of their DNS no‑logs claims in the excerpts provided [3] [2].
4. Big operators (Google/OpenDNS, Level 3) and the difference between transparency reports and audits
Google Public DNS and legacy OpenDNS are widely documented for scale and clear public privacy documentation — Google’s docs explain what it retains and how it uses DNS data — but the reporting in these snippets frames those controls as transparency/policy rather than an independent audit that verifies a no‑logs claim [1] [4]. Level 3/CenturyLink and similar resolvers appear in “best of” lists for speed and reliability but without cited independent privacy audits in the provided material [4].
5. How to interpret “audited” and the limits of available reporting
The available reporting makes an important distinction echoed across VPN/DNS coverage: an audit’s date, scope, and scope depth matter — an audit of policy documents is not the same as one that examines server configurations, authentication flows, or forensic logging practices — and anything older than roughly 24 months is treated as stale in some analyst commentary [5]. Several sources emphasize reading audit reports directly and checking whether they cover server configs and retention behavior rather than marketing claims [5] [6].
Conclusion: verifiable audit winners — and a gray field
Based on the provided reporting, Cloudflare stands out as a DNS resolver with explicitly cited independent audits (KPMG) and public reporting that speak directly to its no‑logs commitments [1]; Quad9 and others present strong transparency postures and documented privacy policies but, in the excerpts supplied, do not have the same clearly cited, recurring third‑party audit reports; numerous other providers (NextDNS, Mullvad DNS, Google Public DNS, Level3/OpenDNS) feature verifiable privacy claims or transparency reporting in the literature but lack, in these sources, a consistent citation demonstrating an independent audit expressly validating a no‑logs claim [2] [3] [4]. Readers seeking provable assurances should follow up by reading the providers’ published audit reports and checking audit firm names, report dates, and the technical scope of verification rather than relying on marketing language alone [5].