Guide per DNS host

Set up DKIM at Cloudflare

DKIM signs outgoing mail with a key whose public part lives in DNS. Cloudflare does not run mailboxes: the key comes from the mail provider, the DNS record is created at Cloudflare. This guide shows both steps and the mistakes that invalidate the signature.

Enable DKIM at Cloudflare

The mail provider generates the key: Microsoft 365 shows two CNAME records (selector1._domainkey and selector2._domainkey) in the admin center under email authentication, Google Workspace a TXT record under google._domainkey in the admin console. These records are created at Cloudflare, then DKIM is switched on at the provider.

Other senders sign separately

Every service sending on behalf of the domain needs its own DKIM key with its own selector: the newsletter tool, the CRM, Microsoft 365. The records do not interfere because each lives under a different selector. DMARC then covers all of them.

How to add the DKIM record at Cloudflare

The way to the Cloudflare DNS editor:

  • In the Cloudflare dashboard open the domain and choose "DNS" → "Records".
  • Choose "Add record" and enter type, name and content.
  • For MX, TXT and mail-related CNAME records keep the proxy status on "DNS only"; the orange cloud belongs to web records only.
  • Type and name as shown by the mail provider: usually CNAME or TXT under selector._domainkey. The selector name goes before _domainkey, the host appends the rest of the domain.
  • Save; Cloudflare propagates instantly.

Typical mistakes at Cloudflare

  • Selector missing or misspelled in the name, so the receiver finds no key.
  • TXT value truncated for long keys or split into several records.
  • CNAME next to other records on the same name.
  • DKIM enabled in the control panel but the name servers are elsewhere and the record is missing there.

Verify and keep an eye on it

After saving, the change at Cloudflare usually applies within minutes. The checker below queries the authoritative name servers and shows right away whether the DKIM record is read correctly. DomainWarn keeps checking the record afterwards and alerts you when it changes or disappears, for example after a migration or one click too many in the DNS editor.

Frequently asked questions

Why does the checker find no DKIM record after enabling it at Cloudflare?
Either the name servers are not at Cloudflare and the record is missing there, or the selector differs from the common ones. Enter the selector name from the Cloudflare control panel in the DKIM checker.
Which key length is right?
2048 bits. 1024 bits is considered too short, longer keys do not fit every DNS editor.
Check now

Free DKIM record check and lookup: selector, key type, key length, syntax and revoked keys. Leave the selector empty to try common selectors automatically.

Selector is optional: leave it empty to check common selectors automatically.

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The same guide for other hosts