Domain Name System (DNS) Trace Analyzer

Introduction:

Domain name delegation shows how queries move from the root to a target and which nameservers answer at each step. It helps you check reachability and find slow paths when answers look inconsistent.

You provide one domain and receive a clear list of zones from the root to the full name, the answering nameservers, and the final addresses. Comparing Internet Protocol version 4 and version 6 answers can highlight gaps or missing records.

When the name is an alias the chain of canonical names is displayed so you can see where traffic will land. This makes content delivery setups and redirects easier to verify and easier to explain to others.

Supply a single domain only. Extra lines are ignored with a short notice. A valid looking pattern does not prove that a service is reachable or active, so confirm with a live test when in doubt.

For consistent results rerun the same check with the same resolver and repeat once to rule out transient errors. Small timing differences are normal on cacheable data.

Technical Details:

The Domain Name System (DNS) delegation path is traced by querying nameserver (NS) records for each relevant zone and then resolving address records at the terminal name. Address lookups include IPv4 “A” records and, when enabled, IPv6 “AAAA” records. If a name is an alias, the Canonical Name (CNAME) chain is followed to its terminal target.

The app constructs a zone list from the input host’s successive suffixes plus the root, then queries NS sets for each zone using DNS over HTTPS to a selected public resolver. Optionally, it resolves addresses for each authoritative nameserver to display their IPs. CNAME following is capped at ten hops with loop detection.

Results are presented as an ordered set of hops with zones and their responding nameservers, followed by the terminal name and its addresses. When no address is present, the last row states “No A record” or “No A/AAAA record,” depending on the IPv6 setting. Outcomes reflect the chosen resolver’s view and cache state at the time of the query.

Comparisons are most meaningful when you keep the resolver selection constant. Differences between resolvers may reflect geography, policy, filtering, or timing. This is a snapshot tool and does not model time-to-live or propagation windows.

Networking & storage behavior

• Queries are issued from the browser to the selected DNS over HTTPS resolver.
• Resolvers: Cloudflare (https://cloudflare-dns.com/dns-query), Google (https://dns.google/dns-query), Quad9 (https://dns.quad9.net/dns-query).
• CSV, JSON, and DOCX are generated client‑side for copying or download.
• No server‑side storage is used by this page.

Performance & complexity

Time grows with zone depth, nameserver count, and the “Show NS IPs” option. CNAME following adds up to ten additional lookups.

Diagnostics & determinism

Identical inputs with the same resolver produce the same steps, subject to resolver policy and cache state. A short debounce reduces needless repeats while typing.

Security considerations

• Input is sanitized to domain‑likeness before queries are attempted.
• Queries reveal the domain names to the chosen resolver. Avoid sensitive targets on untrusted networks.
• Only NS, A, AAAA, and CNAME records are handled in this view.

Assumptions & limitations

• Heads‑up Internationalized domains are not parsed; only ASCII labels are accepted.
• At least two labels are required for a host to be considered domain‑like.
• Label length is limited to 63 characters; overall length to 253 characters.
• Trailing dots are stripped; consecutive dots are rejected.
• Only the first non‑empty input line is used; extras are ignored with a notice.
• NS IP resolution is optional and may be slower on large NS sets.
• CNAME chains are limited to ten hops with loop detection.
• Results reflect resolver perspective and may differ across providers.

Edge cases & error sources

• Resolver unreachable or blocked by network policy.
• Temporary resolver cache differences producing inconsistent answers.
• CNAME loops truncated at the hop limit.
• No A record when IPv6 only targets exist.
• “No A/AAAA record” when terminal has no matching addresses.
• Mixed‑case or whitespace in input before parsing.
• URL parsing failures on malformed http(s):// inputs.
• Large nameserver lists delaying “Show NS IPs.”
• Typing changes mid‑trace cancel and restart the run.
• Domains with single label or invalid characters are rejected.

Scientific & standards backing

DNS concepts follow the core specifications for naming and delegation (RFC 1034 and RFC 1035), IPv6 AAAA records (RFC 3596), and DNS over HTTPS behavior (RFC 8484).

Privacy & compliance

Processing occurs in the browser. DNS queries are sent to the selected public resolver. No data is transmitted or stored server‑side beyond those lookups.

How to Use:

Domain delegation tracing and address comparison in five quick steps.

1. Enter a domain such as example.com.
2. Pick a resolver to match your investigation.
3. Optionally enable Resolve IPv6 and Show NS IPs.
4. Turn on Follow CNAME if aliases are suspected.
5. Run the trace, then copy JSON or table rows as needed.

• Copy a single row to compare specific hops across resolvers.
• Download JSON to preserve inputs, warnings, steps, and addresses together.

FAQ:

Troubleshooting:

• “Enter a valid domain.” — Check for at least two labels and ASCII characters only.
• Empty answers — Try a different resolver or rerun to bypass cache timing.
• Slow run — Disable “Show NS IPs” to cut extra lookups.
• Unexpected terminal — Enable “Follow CNAME” to reveal alias targets.
• IPv6 missing — Turn on the IPv6 toggle and rerun.
• Copy feedback not shown — Wait briefly; the status resets after confirmation.

Advanced Tips:

• Tip Keep the resolver fixed when comparing before and after changes.
• Tip Turn on nameserver IP display to spot anycast diversity or gaps.
• Tip Follow the CNAME chain when fronted by a CDN to confirm the landing host.
• Tip Rerun after a change to observe cache coherence across zones.
• Tip Copy single rows to compare specific zones across different traces.
• Tip Use a URL input to avoid mistakes when the host is embedded in a link.

Glossary:

Delegation

Authority passed from a parent zone to child nameservers.

Nameserver (NS)

A host that answers queries for a zone.

A record

An address mapping to an IPv4 host.

AAAA record

An address mapping to an IPv6 host.

CNAME

An alias that points one name to another.

Root zone

The apex of the naming hierarchy, written as a dot.

Zone

A contiguous section of the namespace served by an authority.

Resolver

A service that performs queries on your behalf.