What Is a Nameserver?

A nameserver is a server that answers DNS questions. For a domain, authoritative nameservers publish the zone's answers, while recursive resolvers look up and cache those answers for users. Changing the nameservers listed for a registration changes where the internet goes to find that domain's DNS data.

Delegation connects the layers

A parent zone points to the nameservers for a child zone using NS records. For example, a top-level domain can delegate example.com to a pair of nameserver hostnames. A resolver follows that delegation and asks the authoritative service for an A, MX, or other record. The nameserver name is not itself the website's address.

A nameserver may be operated by a hosting company, a specialist DNS provider, or the organization that owns the domain. Usually more than one authoritative server is published for resilience.

What happens during a switch

Before replacing nameservers at a registrar, copy the required records to the new DNS provider and check them there. Include web addresses, MX and mail verification records, subdomains, and any DNSSEC configuration. If the new zone lacks an MX record, mail can fail even if the website remains reachable. After the switch, old cached delegation and answers may still be observed for some time.

A common mistake is editing the old provider's zone after delegation moved away. That panel can show a correct-looking record that no longer serves authoritative answers.

How to investigate a mismatch

Use /whois to inspect the visible NS and other DNS records. Compare those with the registrar's configured nameservers and the new provider's zone. If records disagree, check which nameservers are currently authoritative before changing values. The DNS checking guide gives a repeatable sequence. Do not equate a nameserver mismatch with an unregistered domain.

Sources

• RFC 1034: zones and delegation
• RFC 1035: NS resource records