Guide per DNS host

Set up DKIM at Hetzner

DKIM signs outgoing mail with a key whose public part lives in DNS. At Hetzner the key is generated in the control panel; if the name servers are at Hetzner too, the DNS record is usually set automatically. This guide shows both steps and the mistakes that invalidate the signature.

Enable DKIM at Hetzner

In konsoleH generate the key under "Email" → "DKIM" and create the TXT record shown (selector dkim) in DNS.

Hetzner names the SPF value under "Email" → "SPF"; include:spf.your-server.de is common for web hosting packages.

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 Hetzner

The way to the Hetzner DNS editor:

  • Open the Hetzner DNS Console (dns.hetzner.com) and select the zone of the domain.
  • Choose "Add record", enter type, name and value, lower the TTL if needed.
  • 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; the Hetzner name servers serve the record immediately.

Typical mistakes at Hetzner

  • 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 Hetzner 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 Hetzner?
Either the name servers are not at Hetzner and the record is missing there, or the selector differs from the common ones. Enter the selector name from the Hetzner 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.

DomainWarn checks SPF, DKIM, DMARC, DNS and certificates of all client domains regularly and reports changes before mail lands in spam.

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The same guide for other hosts