Good morning, afternoon, evening Reddit.

So, I have been asked to set up a DMARC record for my company. We currently use Exchange Online for our email service.

I configured the DMARC settings with the p=none value, setup a postmaster mailbox and reviewed the results for a few days. Everything was going ok, so I switched the value to reject.

Email began getting caught in quarentine, which shoud have not been. Specifically, we use a third party company to send email campaigns on behalf of ourselves.

The emails are received by the third party and then forwarded to an internal mailbox - these were caught up in the Exchange Quarentine section, which i then had to release.

After a bit of afternoon stress, I reverted value on my DMARC back to p=none and everything was working.

Having reviewed everything and read a number of posts on this sub, I think i'm getting there but it's still confusing. I've used this really cool site posted on this sub which was able to direct me to running a SPF,DMARC,DKIM test against my domain and it's the DKIM section which fails.

">> Running Identifier Alignment verification

SPF domain "domain_name.co.uk" aligns with the RFC5322.From domain domain_name.co.uk. Alignment is pass.

DKIM domain does not align with RFC5322.From domain (domain_name.onmicrosoft.com != domain_name.co.uk). Alignment mode: relaxed.

>> Finalizing DMARC

SPF auth result is pass and SPF domain is in alignment. DMARC SPF result is pass.

DKIM auth result is pass, but the DKIM domain is not in alignment. DMARC DKIM result is fail.

Because the SPF test passed and the domains are in alignment, the DMARC result is pass"

So, a couple of thoughts - most obvious one is that I think I need to sort out this DKIM stuff on my exchange online platform - can someone verify?

Also, once i've set this up on exchange online, do i then need to set it up on the third party site as well? If so, how would i do this?

Any help would be great!

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