Inventory all zones served by the nameserver, its IPv4/IPv6 addresses, registered host objects, glue and authoritative address records. Obtain access to the relevant registrar and DNS infrastructure. Keep the old address allocated and operational during the transition.

1. Prepare the new server or listener and copy the authorised zone configuration through a secure supported method. Query it directly by IP for several representative customer zones.
2. Confirm UDP and TCP DNS, secondary synchronisation, DNSSEC signing arrangements and monitoring on the new address. A responding daemon with no customer zones is not ready.
3. Lower address-record TTLs ahead of time where practical, allowing the old TTL to expire. Identify parent glue TTLs that you cannot control and include them in the overlap plan.
4. Update the nameserver hostname's authoritative A/AAAA records and the corresponding registrar host/glue data. Keep unchanged nameserver names in customer delegations unless the migration also intentionally changes those names.
5. Monitor queries and failures while old cached addresses remain valid. Retire the old listener only after the relevant caches and operational checks support that decision.

Trace multiple customer domains through different parent zones and query each listed nameserver. Verify authoritative answers, signed-zone validation and consistency of the hostname's forward addresses and parent glue.

If failures affect only part of the portfolio, compare those domains' parent referrals and the zones loaded on the new server. Restore or retain the working old address while correcting missing zones or stale host data.

• Fix a private nameserver delegation that depends on missing glue
• Diagnose a listed nameserver that does not serve the delegated zone
• Move a signed domain to another DNS provider without a stale DS record
• Prepare a reversible DNS change with an exact before-and-after record list

• RFC 9471
• RFC 1034
• RFC 7766