# Free DNS tools: lookup, CNAME chains, verification and diff

> Free DNS tools: detect providers, compare authoritative and public answers, follow CNAME chains, diagnose verification and diff expected records.

- Canonical HTML page: https://dodomain.io/tools
- This Markdown twin: https://dodomain.io/tools.md
- Site index for agents: https://dodomain.io/llms.txt
- Full documentation as Markdown: https://dodomain.io/docs/llms-full.txt

Generated at build time from the same React source the HTML page renders, never a hand-maintained second copy. Every public page on this host has a twin at `<url>.md`.

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Free tools

## The DNS checks we run for customers, free for anyone

FreeNo accountWorks without JavaScript

Each tool below is the same engine DoDomain uses to connect and verify customer domains, pointed at a domain you type in. The record checks read the zone's own authoritative nameservers, not a cache (the SPF checker follows its includes through a public resolver), and they say *not probed* where they did not look rather than guessing. No account, no JavaScript required.

### Find the DNS host

1 tool

- #### [DNS provider detector](https://dodomain.io/tools/provider-detector)
  
  Which DNS host serves a domain, and whether one-click setup is available there.

### Check records

4 tools

- #### [DNS propagation checker](https://dodomain.io/tools/dns-lookup)
  
  One record, read from the authoritative nameservers and three public resolvers.
- #### [SPF record checker](https://dodomain.io/tools/spf-checker)
  
  Parse a domain's SPF, walk its includes, count the lookups against the limit of ten.
- #### [CNAME chain checker](https://dodomain.io/tools/cname-chain)
  
  Follow aliases and flag loops, apex CNAMEs and possible flattening.
- #### [Domain verification diagnoser](https://dodomain.io/tools/verify-diagnoser)
  
  Compare a domain with its expected target and find the provider's fix instructions.

### Compare

1 tool

- #### [DNS record diff](https://dodomain.io/tools/dns-diff)
  
  Compare a live DNS snapshot with the expected records you paste in.

### Need this inside your product?

The provider detector is `POST /api/v1/domains/check` in the DoDomain API, and the verification behind the propagation checker is what runs on every custom-domain connection. The free plan includes both.

[Start free](https://app.dodomain.io/signin?mode=signup) [Read the docs](https://dodomain.io/docs)