DKIM Checker Articles

DKIM Key Length and Algorithm: Why "Still Validates" Doesn't Mean "Still Recommended"

A DKIM key generated five years ago might still be using RSA-1024 — a length that was acceptable then but has since been "softly" deprecated by major providers, even though signatures using it still technically validate. Here's how to identify your key's algorithm and length from its DNS record, why Ed25519 is the emerging alternative (and why dual-key signing addresses its adoption gap), and why this migration follows the same process as any DKIM key rotation.

Jun 16, 2026

DKIM, Mailing Lists, and Forwarding: Why Signatures Break and How ARC Tries to Help

A correctly signed email can fail DKIM verification at the recipient simply because a mailing list added an unsubscribe footer — modifying the signed content. Here's why mailing lists and forwarding break DKIM, how ARC (Authenticated Received Chain) was designed to preserve authentication results through intermediaries, and why SPF and DKIM respond differently to forwarding.

Jun 16, 2026

The Complete Email Authentication Audit: How to Check SPF, DKIM, DMARC, PTR, and BIMI

Most organisations have never systematically audited their full email authentication stack. Here's the complete 8-step process: inventorying all sending services, auditing SPF, DKIM, DMARC, PTR, and BIMI, sending a test to verify all pass, and setting up ongoing monitoring.

Jun 9, 2026

DKIM Key Rotation, Multiple Selectors, and Debugging Silent Failures

DKIM breaks silently and the symptoms look like spam problems. Here's key rotation without disruption, why DKIM alignment matters for DMARC, multiple selectors for multiple sending sources, and how to debug the most common failure modes.

Jun 8, 2026

DKIM Checker — Verify Your Domain's Email Signing Key in DNS

Learn how DKIM works, what a DKIM DNS record contains, how to find your selector, and how to use a free DKIM checker to verify your email signing key is correctly published.

Jun 6, 2026