Adding a DKIM record

DKIM adds a digital signature to every email you send. The recipient verifies that signature with a key published in your DNS. The recipient can then see that the email really comes from your domain and was not altered on the way. This helps keep your mail out of spam folders.

What you need

Your email provider gives you two things:

• a selector: a short name, for example default, x or selector1;
• a public key: a long text starting with v=DKIM1; k=rsa; p=.

With Knippin web hosting, you find these in DirectAdmin under E-mail Management → DKIM. Using Microsoft 365 or Google Workspace? Then you find them in their admin centre.

Adding it in the customer panel

1. Go to Services → Domains, click the domain and choose Manage DNS records.
2. Add a record:
   • Name: the selector followed by ._domainkey, for example default._domainkey;
   • Type: TXT. For Microsoft 365 it is a CNAME pointing to the address Microsoft gives you;
   • Value: the public key, without quotes.
3. Click Add.

You do not need to split a long key yourself. Paste the whole key into the field. The DNS server splits it where needed.

Checking

Send an email to your own Gmail address and choose Show original there. DKIM should say PASS. You can also run a test at mail-tester.com.

Several mail systems for the same domain, for example your mail server and a newsletter service? Each system then has its own selector and therefore its own DKIM record.

See also Setting up SPF and DMARC.