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DKIM — glossary

TL;DR

DomainKeys Identified Mail — cryptographic signature in DNS proving message integrity.

Key facts

Term
DKIM

TL;DR

DKIM (DomainKeys Identified Mail) adds a cryptographic signature to outbound messages and publishes the public key in DNS. Receivers verify the signature to detect tampering and spoofing.

Common failures

  • DKIM enabled in cPanel but the TXT record never published to authoritative DNS
  • Wrong selector (default._domainkey vs cpanel._domainkey)
  • External DNS (Cloudflare) while keys only exist in a stale WHM zone copy

Hosting reseller tip

Enable DKIM in cPanel, then confirm the _domainkey TXT record is visible on the public nameservers — not just in WHM's local zone file.

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