Verify DKIM and Spam protections on 365

Joe Danyi
Joe Danyi used Ask the Experts™
We have an office 365 tenant with about 20 some users, we have been receiving a lot of spam though our domain, among other things we recently setup and turned on DKIM. Since that time we did receive spam but interestingly we received phishing emails from the same domain name that we believed DKIM would block.
Do you know of any way to verify if DKim is working?
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Distinguished Expert 2018

DKIM did not protect from incoming spam messages

DKIM is there for outbound messages

What O365 plan you are on?

Check if your tenant is subject to basic Exchange online Protection (EOP), if required you may log call with O365 support, its free
Also check other possibility like anybody else already built another server with your domain name and trying to spam attack, you need to check received spam message headers....
Computer Technician
Top Expert 2015
To verify if DKIM is working send an empty email to and wait about 30-45 seconds for a reply. The return email should say...

DKIM check:         pass
Most Valuable Expert 2015
Distinguished Expert 2018

To add to the above, I'd recommend you review the following article/whitepaper to get a better understanding of what O365 can protect you against:

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