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IONOS: set up SPF, DKIM and DMARC step by step

5 min read · updated 1 Nov 2026 · Timo Kessel

If your domain is with IONOS, you create SPF, DKIM and DMARC in the DNS settings of the domain. Here is where to find them, what IONOS provides for this and what to watch for with DKIM and DMARC. As of 1 November 2026.

IONOS's interface changes from time to time. The notes on SPF come from the IONOS help, those on DKIM and DMARC from third-party guides, retrieved on 1 November 2026. Check the exact values in your IONOS account or mail package before entering anything.

First: who manages the DNS?

If your domain is at IONOS with the IONOS name servers, you create the records there. If the DNS is elsewhere (for example at Cloudflare), the records must be there, even if your email runs through IONOS. The domain check shows what is in DNS today.

Opening the DNS settings at IONOS

  1. Log in to IONOS and open the management of the domain.
  2. Go to the DNS settings of the domain.
  3. With Add record you create new records.

Changes can take up to 24 hours to apply everywhere. It is better to change SPF, DKIM and DMARC one after the other so you can assign errors to the right record.

SPF

When adding a record you can, according to the IONOS help, choose the record type “IONOS SPF (TXT)” and save. This creates a TXT record for sending through IONOS; according to the help no further steps are needed.

If services other than IONOS also send in your name (newsletter tool, invoicing program), they belong in the same record. A domain may have only one SPF record, two cause an error (fixing SPF PermError). The SPF generator builds the right record.

DKIM

If you use the IONOS mail package and IONOS manages your DNS, IONOS provides the required DKIM records (CNAME), according to third-party guides. If the DNS is with another provider, you must publish the records IONOS names there. Your IONOS account gives the exact names and targets, take them from there and not from an example.

Whether the records arrive is shown by the DKIM checker. If you send through another service, it gets its own key (DKIM generator, finding the selector).

DMARC

DMARC is a TXT record named _dmarc. In the name field enter only _dmarc, without your domain, because IONOS adds it itself. Start with p=none:

v=DMARC1; p=none; rua=mailto:reports@your-domain.com

The DMARC generator builds the finished record. With a free account Postwacht analyzes the reports and tells you when quarantine and later reject are safe (analyzing DMARC reports). If _dmarc already exists, edit the existing record instead of creating a second one.

Checking

  1. Wait until the records are visible (usually minutes, 24 hours at most).
  2. Check everything at once with the domain check.
  3. Send an email to a test address in the email test. It shows whether SPF and DKIM pass and align on a real email.

Frequently asked questions

My DMARC record cannot be created.

Usually _dmarc already exists, or the name additionally contains the domain. Edit the existing record and enter only _dmarc as the name.

Why does the checker not show my DKIM key?

Either the record is not active yet, or the selector is not one of the common ones. Enter it in the DKIM checker.

Is the information still correct?

It comes from help pages and guides of 1 November 2026. If you notice anything different, write to us via support.

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