Nameserver Lookup

Nameserver lookup: who answers for a domain?

Every domain delegates its DNS to a set of authoritative nameservers. Those servers hold the zone and give the final answer for its A, MX, TXT and other records. A nameserver lookup reads the domain's NS records, so you can tell which DNS provider is actually in charge.

Example

TYPE  TTL     VALUE
NS    86400   ns1.provider.example
NS    86400   ns2.provider.example

The values are illustrative. Real results often come from large DNS hosts and list two to four servers, frequently on different networks for resilience.

Two places NS records live

Delegation involves two copies of the NS set:

• At the parent zone. When you set nameservers at your registrar, the registry publishes them in the TLD zone (for .com, on servers such as a.gtld-servers.net). This is what directs resolvers to your provider.
• Inside your own zone. Your DNS provider also publishes NS records at the top of the zone. They should match the parent's list.

When the two disagree, or when a listed server does not actually host the zone, you have a lame delegation. Some lookups then succeed and others fail, depending on which server a resolver picks.

Changing DNS providers

1. Recreate every record at the new provider before you switch.
2. Change the nameservers at your registrar.
3. Keep the old provider's zone running for a few days. The delegation records in TLD zones often carry long TTLs (two days for .com), so some resolvers will keep asking the old servers for a while.

This tool asks a recursive resolver, so right after a switch it may still show the old set. To see what the registry publishes now, query the parent directly:

dig NS example.com @a.gtld-servers.net
dig +trace example.com

Using the results

Once you know the authoritative servers, you can query them directly to bypass caches, which is the reliable way to confirm a new record. Look up the other records of the zone with the full DNS lookup, check that each nameserver hostname resolves with Hostname to IP, and verify mail-related entries with TXT Record Lookup.

Reading the nameserver names

Nameserver hostnames usually follow a provider's naming scheme, which tells you where the zone is managed:

Names inside the domain itself, such as ns1.example.com, are vanity or self-hosted nameservers. They need glue records at the registry, meaning the IP addresses of those hosts published in the parent zone, because otherwise resolvers could not reach the servers that answer for the domain they live in.

Privacy

This is a server-side lookup: the domain you enter is sent to our server, which runs the DNS query. The tool does not keep a record of your lookups.