NSEC Lookup
Lookup NSEC records and inspect authenticated denial of existence signals.
Use NSEC Lookup in 4 Steps
What is NSEC Lookup?
NSEC Lookup is used to lookup dnssec nsec records. This route is designed for fast operational diagnostics with clear educational context.
NSEC records provide authenticated denial of existence by linking signed names in canonical order.
During migrations or incidents, this check helps determine whether issues are caused by source configuration, resolver caching, or dependency records.
Why It Matters in DNS Operations
- Source verification: confirm live resolver output before broader rollback actions.
- Change windows: detect whether updates are visible where expected.
- Incident triage: narrow likely root-cause early with specific record evidence.
- Team alignment: share URL-state checks to avoid duplicated investigation.
- Best use: Diagnosing NXDOMAIN validation and zone-enumeration behavior.
Quick Interpretation Table
| Observed Result | Likely Cause | Next Step |
|---|---|---|
| No NSEC/NSEC3 on NXDOMAIN | Invalid denial proof | Check signer denial configuration |
| Broken next-name chain | Zone walk proof inconsistency | Re-sign and re-publish zone |
| Signature invalid on NSEC | Proof cannot be trusted | Regenerate signatures and verify keyset |
Troubleshooting Workflow
- Run this record check first for scoped signal.
- Validate nameserver authority and SOA context if results are unexpected.
- Use propagation checks when regions return mixed outcomes.
- Re-run after fixes and compare values against expected policy.
Common Misconfiguration to Avoid
Assuming denial proofs are optional when DNSSEC is enabled.
Validation Path
NXDOMAIN responses should include valid denial records and matching signatures.
Data Source and Limitations
Tools provide actionable lookup output where feasible and clear guidance for deeper verification paths. For high-impact production incidents, pair with provider logs and CLI validation.