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The registry and the zone disagree about the nameservers

MediumConfirmeddns.health.ns-parent-child-mismatch

What this check looks for

The nameserver list held at your registry is not the list your own zone publishes. Which one a visitor uses depends on their resolver, so the domain behaves differently for different people.

Why it matters

This is how a nameserver you decommissioned months ago keeps taking traffic. Resolvers that learned the delegation from the registry keep asking the old server; resolvers that learned it from your zone ask the new one. Both are following the rules, and the two get different answers.

When the check passes, your report says: “The registry and the zone agree on the nameserver list”.

What it costs your score

When this check fails it removes 8 points from your DNS score, before the status, confidence and repeat multipliers are applied. DNS carries a weight of 10 in the overall score.

It shares the dns.health.delegation family ceiling of 35 points: however many findings that family produces, together they cannot remove more than that from DNS. One underlying problem showing up in several places is still one problem.

Severity
medium
Default confidence
confirmed
Status when triggered
warn
Deduction
8 points
Family cap
dns.health.delegation · 35
Category
DNS
Module
Dns health
Fix owned by
registrar
In the ruleset since
2026.09

How the whole score is calculated

How to fix it

Make the NS set at the registrar and the NS records in the zone identical.

While they differ, some resolvers use nameservers you thought you had removed.

  1. Decide which list is correct — normally the one your DNS provider currently serves.

  2. Update the delegation at the registrar to match it exactly.

  3. Update the apex NS records in the zone to match it exactly.

  4. Wait for the parent's NS TTL (often 2 days) before concluding that a stale server has stopped receiving traffic.

How to confirm it worked

  • dig +short NS ‹domain› — the zone's own list

  • dig +norecurse @<tld-nameserver> NS ‹domain› — the registry's list; the two must match

A named slot like ‹domain› — and the braces left in the configuration below — is filled in with your own values when this rule appears on a report.

Technical detail

Only at the registry: ‹only parent›. Only in the zone: ‹only child›. RFC 1034 §4.2.2 expects the delegating NS set and the zone's own apex NS set to be identical; RFC 2181 §5.4.1 makes the zone's own copy authoritative, but the registry's copy is what a resolver finds first, so both are used in practice. Fix both sides, not one.

Standards and references

Test this on your domain

Run the check that produces this finding, on its own, against any domain.

Open the dns health checkerBuild the fix

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