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DKIM Lookup

Available

Look up the DKIM public key published at selector._domainkey.domain and check its format, key type and length.

DKIM Lookup

Domain name

DKIM selector (s= in the DKIM-Signature header)

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How it works

The server queries the TXT record at <selector>._domainkey.<domain>, parses the v, k and p tags and reports the key type and size.

Safeguards & responsible use

  • Only public domain names are accepted; internal names (.local, .internal, …) are rejected.
  • Queries go to public resolvers, never to internal DNS.
  • Per-client rate limiting and query timeouts.

Frequently asked questions

How do I find my DKIM selector?

Open the headers of a message you sent and look for s= in the DKIM-Signature header — or use the Email Header Analyzer.

What key length should I use?

2048-bit RSA is the common recommendation; 1024-bit keys are considered weak.