Diagnose mail DNS failures
Separate authoritative errors, cache staleness, and delegation problems.
- Difficulty:
- Intermediate
- Prerequisites:
- Failing name and symptom
- Last updated:
- 2026-07-15
- Author:
- empire
Steps
- Query the authorityAsk authoritative servers directly for the RRset.
- Compare recursive answersCheck whether recursive resolvers still cache prior data.
- Inspect delegationValidate NS and glue if authority cannot be reached cleanly.
Expected outcome: Failure class identified with next remediation step.