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Set up DKIM for Exchange online (Microsoft 365).

How to enable DKIM signing in the Microsoft 365 Defender portal.


  • Switch to the DKIM page in the Microsoft 365 Defender portal: https://security.microsoft.com/dkimv2.
  • Choose your domain
  • Update your DNS settings as follows::
    Create 2 CNAME records..

    Replace “YYY” with your domain
    Replace “XXX” with your Microsoft Tenant prefix

    Host Name : selector1._domainkey Points to address or value: selector1-YYY._domainkey.XXX.onmicrosoft.com
    Host Name : selector2._domainkey Points to address or value: selector2-YYY._domainkey.XXX.onmicrosoft.com
  • If you published the CNAME records, the sync will take up to 4 days. If you get an error message, come back and repeat the last step.
  • Then select Sign messages for this domain with DKIM signatures in Enabled (Ein-/Ausschalten).)


If everything worked, the result looks like this:

Dieser Beitrag ist auch verfügbar auf: Deutsch (German)

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Published on - 31. May 2023
Modified on - 27. Mar 2024
Views - 184
Likes - 0

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