---
title: "Bulk DNS Lookup — free tool"
description: "Free bulk DNS lookup. Resolve A, MX, NS, TXT records for up to 25 domains in one batch. CSV export, no signup."
canonical: "https://lemwatch.com/tools/bulk-dns-lookup"
source: "https://lemwatch.com"
---

# 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

- A and AAAA records (IPv4 / IPv6)
- MX records (mail servers)
- NS records (authoritative nameservers)
- TXT records (SPF, DMARC, verification tokens)
- CNAME chains

## 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

- Diff today's CSV against last month's — any unexpected A-record change is a flag
- Verify every domain has an SPF TXT record (v=spf1 …) — missing SPF tanks deliverability
- Ensure every production domain has DMARC (v=DMARC1 …) at least in p=none for visibility
- Watch for CNAMEs pointing at services you no longer use — those are subdomain-takeover risks

## 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.


## Related

- [All free tools](https://lemwatch.com/tools)
- [DNS Lookup](https://lemwatch.com/tools/dns-lookup)
- [Bulk SSL Certificate Checker](https://lemwatch.com/tools/bulk-ssl-checker)
- [Bulk Security Header Checker](https://lemwatch.com/tools/bulk-security-headers)
- [Bulk Meta Tag Checker](https://lemwatch.com/tools/bulk-meta-tags)
- [Bulk Mobile-Friendly Test](https://lemwatch.com/tools/bulk-mobile-friendly)
- [Lemwatch pricing](https://lemwatch.com/pricing)
- [All monitoring checks](https://lemwatch.com/features)