DKIM Setup with Office 365

Hello, I was testing our DKIM entries in DNS and noticed that the CNAME name value is not the same as what is entered.

Here is what Microsofts documentation shows the entries should be…

Example: If your custom domain is contoso^com and your initial domain is contosocompany.onmicrosoft^com, the CNAME records look like this:

Host name: selector1._domainkey.contoso^com

Points to address or value: selector1-contoso-com._domainkey. contosocompany.onmicrosoft^com

When I enter in the CNAME value using the example above and replace contoso^com with our actual domain name, it drops the .contoso^com… so the retained value reads as selector1._domainkey

(had to replace ". " with a “^” as links are not allowed in the post)

Is this normal?
Why is it dropping the domain name?
How do I correct it if the domain name is supposed to be there?

The Cloudflare UI drops the domain name from the display, but it’s there in DNS. You can double-check the entry by looking up the record, either from a command-line tool like dig or host, or one of the many DNS checking websites like this one.

This is the way DNS setup has worked for decades–you would have a manually-created zone file and the root domain would be appended automatically so you don’t have to type it out every time. They continued this into the modern UI.

2 Likes

Thank you for the clarification! I was able to check using mxtoolbox.

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