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Free DKIM Record Lookup

Auto-discover DKIM records across 50+ common selectors, or look up a specific selector. Identify which email services sign messages for your domain.

No signup required — auto-discovers SendGrid, Google, Microsoft 365, and 100+ providers

Scans common DKIM selectors via DNS-over-HTTPS to discover which email services sign messages for your domain.

What is a DKIM Record?

A DKIM (DomainKeys Identified Mail) record is a DNS entry that enables email senders to sign outgoing messages with a unique cryptographic signature. This signature acts as a digital fingerprint, allowing recipients to verify that an email genuinely originated from the claimed domain and hasn't been altered in transit.

Think of it like receiving a letter sealed with a wax stamp — the stamp indicates the letter is authentic and hasn't been tampered with during its journey. As of 2023, approximately 80% of Fortune 500 companies use DKIM to secure their email communications.

How DKIM Authentication Works

1

Generate Key Pair

A DKIM inspector discovers existing DKIM selectors and public keys (kept secret on your mail server) and a public key (published in your DNS).

2

Sign Outgoing Emails

Your mail server uses the private key to create a unique encrypted signature for each outgoing email, added to the header.

3

Verify on Receipt

The receiving server retrieves your public key from DNS and verifies the signature. If it matches, the email is trusted.

Common DKIM Issues

Misconfigured DNS Records

Typos or incorrect entries in TXT records are the most common cause. Double-check for missing quotation marks and proper formatting.

Selector Mismatch

Ensure the selector configured on your mail server matches exactly what's in your DNS record. Even minor discrepancies cause failures.

Key Length Incompatibility

Modern security standards recommend 2048-bit keys. If you're using an older system, verify it supports your chosen key length.

DNS Propagation Delays

After making DNS changes, allow several hours for propagation before testing. Changes don't take effect instantly across all nameservers.

DKIM is just one piece of the puzzle

DMARC Report monitors DKIM, SPF, and DMARC alignment together — giving you a complete picture of your email authentication health.

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