Bulk DNS Lookup Tool

Resolve DNS records for up to 25 domains at once. A, AAAA, MX, NS, TXT, CNAME — exported as CSV for diff and audit.

DNS is the silent layer behind every site. When it works, nobody notices. When it drifts — a typo'd A record, a missing SPF, an MX pointing at a defunct mail provider — sites and email break in ways that take hours to debug. Bulk DNS lookups give you a single-pass snapshot of an entire portfolio so you can spot drift before it hurts.

## What this tool does

Paste up to 25 domains. For each, we resolve A, AAAA, MX, NS, TXT, and CNAME records using authoritative DNS lookups and return them in a sortable table. Export the lot to CSV and you have an audit baseline you can re-run weekly and diff.

## When to use it

Pre-migration audits (capture every record before a registrar move). Post-migration verification (confirm everything resolved correctly). Email deliverability sweeps (one CSV column for SPF, one for DMARC, sort by 'missing'). Subdomain-takeover hunts (find CNAMEs pointing at unclaimed S3 buckets, GitHub Pages, or Heroku apps).

What this tool checks

Why it matters

A wrong A record, missing SPF, or dangling CNAME quietly breaks email, monitoring, or a whole subdomain. Across a portfolio, DNS drift is invisible until something is on fire.

How to fix what it finds

Methodology

We resolve each domain against public DNS using Deno's built-in DNS resolver (which delegates to the OS resolver in our edge runtime). For each domain we run six queries in parallel: A, AAAA, MX, NS, TXT, CNAME. Results are joined into a single row per domain. We do NOT use the recursive resolver of any specific provider (no '1.1.1.1' or '8.8.8.8' override) — we use the platform resolver to match what a typical client on the public internet sees. NXDOMAIN responses are surfaced as errors, not silently empty. TXT records are returned as raw strings so you can read SPF/DMARC/verification tokens verbatim.

Frequently asked questions

Are the lookups authoritative?

They are recursive lookups against the public DNS hierarchy — the same path a normal client follows. For authoritative-only queries against a specific NS, use the single-URL DNS Lookup tool which exposes that option.

Why are TXT records truncated?

Long TXT records (DKIM keys especially) can exceed our display width. The full value is in the CSV export — view the column there.

Does this query DNSSEC?

Not in bulk mode. The single-URL DNS Lookup tool surfaces DNSSEC status separately.

How fresh are results?

Live — every lookup is a fresh DNS query. No caching beyond what your platform DNS resolver does.

Can I check NS records to spot delegation issues?

Yes. The NS column shows the authoritative nameservers as returned by the parent zone — handy for catching mid-migration mismatches.

What about CNAME chains?

We resolve one level of CNAME. For multi-hop chains, the single-URL DNS tool walks the chain in full.