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NS Record Lookup (Name Servers)

Identify your domain's authoritative DNS servers

DNS delegation issues? Verify that your NS records point to the correct servers and that they respond properly.

In iterative trace mode, the resolver is ignored.
Query multiple public resolvers to compare answers.

Authoritative servers

Discover which DNS servers are responsible for your zone. Verify their consistency and availability.

Multi-resolver

Compare responses from Google, Cloudflare, and Quad9 to detect propagation issues.

Delegation check

Ensure parent zone NS records match those in your zone. Detect inconsistencies.

TTL and migration

Check each record's TTL to plan your DNS server changes with confidence.

Free and unlimited

Test as many domains as needed. No signup required.

How to use the DNS lookup engine options effectively

What is the iterative trace?

The trace performs resolution step by step. The resolver first queries the root servers, then the TLD (.com, .fr, .eu), and then the authoritative servers of the target zone. At each step, the page shows the queried server, the answer, the RCODE, and the latency.

  1. 1. Root

    Discovery of the TLD servers for the requested name.

  2. 2. TLD

    Reference to the zone's NS (delegation).

  3. 3. Authoritative

    Final answer (or error) with TTL and latency.

What is it for?

  • Compare answers across resolvers and regions
  • Detect a hot cache, an overly long TTL, or an incomplete delegation
  • Explain a latency difference or an unexpected RCODE

Tip: keep the trace disabled for quick checks; enable it when investigating or preparing a ticket/post‑mortem.

What is the classic trace?

The classic trace queries only the selected resolver (UDP or DoH) and displays the answer as it is perceived from that network vantage point. You get the RCODE, the response sections, and the latency for the client → resolver leg.

  1. 1. Chosen resolver

    Uses the preset or custom configuration to run the query exactly like your service would.

  2. 2. Protocol preserved

    Respects the selected transport (UDP, TCP, or DoH) so you reproduce the real behaviour.

  3. 3. Detailed answer

    Shows the question, answer, and authority/additional sections when present, together with TTL and useful metadata.

Why use it?

  • Check the view of a specific resolver before suspecting delegation issues
  • Confirm cached values and the impact of a TTL or a flush
  • Document a resolution exactly as a client or microservice sees it

Tip: keep the iterative trace option turned off when auditing a given resolver; enable it afterwards to compare with the root → TLD → authoritative path.

How does the propagation test work?

The test queries a set of public resolvers (Google, Cloudflare, Quad9, OpenDNS, ISPs…) in parallel and groups the answers by content and RCODE. You instantly see who already picked up the update.

  1. 1. Multi-point resolvers

    Enables the propagation presets to question several actors spread around the world.

  2. 2. Automatic comparison

    Groups identical answers and highlights divergences or resolver-specific errors.

  3. 3. Actionable summary

    Provides a clear recap, the resolver list, their latencies, and each group's status.

When to use it?

  • Track how a DNS change propagates worldwide
  • Spot stale caches and decide on a targeted flush
  • Share a propagation snapshot in a ticket or post-mortem

Tip: while the propagation test is active, the resolver selector is frozen. Disable the mode to return to single-resolver diagnostics.

What is an NS record?

An NS (Name Server) record designates the authoritative DNS servers for a zone. These servers hold the domain's DNS data and respond to queries from recursive resolvers.

NS record structure:

FieldDescriptionExample
NameApex or subdomain@ or subdomain
TypeAlways NSNS
TargetDNS server namens1.provider.com.
TTLCache duration in seconds86400

Usage examples

Servers at apex

Standard authoritative server declaration:

captaindns.com.  86400  IN  NS  ns1.provider.com.
captaindns.com.  86400  IN  NS  ns2.provider.com.

Subdomain delegation

Delegate a subdomain to dedicated servers:

api.captaindns.com.  3600  IN  NS  ns1.api-provider.com.
api.captaindns.com.  3600  IN  NS  ns2.api-provider.com.

Glue records

When the NS server is within the domain it serves:

captaindns.com.      86400  IN  NS  ns1.captaindns.com.
ns1.captaindns.com.  86400  IN  A   203.0.113.10

Important rules

Consistency required

RuleExplanation
Zone = RegistrarNS must be identical in zone and at registrar
Minimum 2 NSRedundancy required for availability
Different networksServers should be geographically distributed

Best practices

PracticeWhy
3-4 NS serversBetter resilience
Long TTL (86400)Zone stability
Glue if neededPrevents resolution loops

Common issues

NS inconsistency

NS in zone differs from registrar. Intermittent resolution.

  1. Check NS in your DNS zone
  2. Compare with registrar delegation
  3. Synchronize both lists

Unreachable NS server

One NS server not responding.

  1. Test each server individually
  2. Verify glue records are correct
  3. Temporarily remove failing server

Non-functional delegation

Delegated subdomain doesn't resolve.

  1. Check NS in parent zone
  2. Ensure target servers are operational
  3. Add glue records if NS are within subdomain

Command line verification

Linux/Mac

dig NS captaindns.com

Check consistency with parent zone:

dig NS captaindns.com @a.gtld-servers.net

Windows

nslookup -type=ns captaindns.com

DNS server migration

  1. Prepare: Configure new servers with complete zone
  2. Lower TTL: Set NS TTL to 300 seconds, wait for old TTL
  3. Update zone: Add new NS in zone
  4. Update registrar: Modify delegation at registrar
  5. Verify: Test from multiple networks
  6. Finalize: Remove old NS, raise TTL

ToolPurpose
A Record LookupCheck NS server IPs
SOA Record LookupCheck zone metadata
DNS Propagation CheckCheck worldwide propagation

Useful resources