DoH Enabled vs Disabled: Which Approach Best Balances Privacy and Compatibility?

Goal

Determine the most reliable method for DNS resolution on Windows 11 when using the built‑in DNS over HTTPS (DoH) client.

Context

Windows 11 offers a native DoH client that can be toggled via the EnableSecureDns registry key. When enabled, the system sends queries to the specified DoH server over HTTPS. If that server is unreachable, the client is expected to fall back to the traditional UDP/TCP DNS server. However, the exact retry policy and timing of this fallback are not documented.

Constraints

• Privacy: DoH encrypts DNS traffic, protecting against ISP‑level snooping.
• Compatibility: Some corporate or legacy applications rely on synchronous DNS responses or local caching.
• Reliability: Unclear if the fallback occurs automatically or requires manual intervention.

Unresolved Decision

Does enabling DoH on Windows 11 guarantee a seamless fallback to the traditional DNS server when the DoH endpoint fails, or must administrators manually configure alternate resolution paths?

Key Questions

1. Will the Windows 11 DoH client automatically retry a traditional DNS query after a DoH failure, and if so, what is the timeout and retry count?
2. Does disabling DoH ensure consistent resolution for legacy corporate applications, or does it expose DNS traffic to potential interception?
3. What observable events or logs can confirm whether the system has successfully switched from DoH to the traditional DNS server?