Does DoH slow down browsing?

Minimally. The first query may be slightly slower, but DoH providers cache aggressively. Most users will not notice any speed difference.

Which DoH provider should I use?

Cloudflare (1.1.1.1) is fast and privacy-focused. Google (8.8.8.8) is reliable. Quad9 (9.9.9.9) adds malware blocking.

Browser DNS-over-HTTPS (DoH) Errors — Secure DNS Configuration Issues

Informationalsecurity

Overview

Fix DNS-over-HTTPS errors including secure DNS lookup failures, DoH provider unreachable, fallback to plain DNS, and corporate network compatibility issues.

Key Details

DNS-over-HTTPS (DoH) encrypts DNS queries, preventing ISP snooping and DNS manipulation
Chrome: Settings > Privacy > Security > Use secure DNS (with custom provider option)
Firefox: Settings > Privacy > DNS over HTTPS (enabled by default in the US)
Corporate networks may use internal DNS that DoH bypasses, breaking intranet access
Some ISPs use DNS for parental controls which DoH circumvents

Common Causes

DoH provider server down or unreachable
Corporate firewall blocking DoH connections (HTTPS to DNS providers)
Internal/intranet DNS names not resolvable via public DoH providers
DNS split-horizon configuration broken by DoH bypassing local resolver
Browser DoH configuration pointing to an invalid or unreachable provider

Steps

1For browsing failures: temporarily disable secure DNS — Chrome > Settings > Privacy > Security > toggle off
2Try a different DoH provider: Cloudflare (1.1.1.1), Google (8.8.8.8), or Quad9 (9.9.9.9)
3For corporate networks: disable DoH or configure it to use company's internal DoH server
4Firefox: about:preferences > Privacy & Security > DNS over HTTPS > change or disable
5Check if DoH is working: use nslookup or browser DevTools Network tab to verify DNS resolution