Cloudflare email routing + exchange online + custom domain

Has anyone set up cloudflare’s email routing feature w/ Exchange Online?

Is it possible to have cloudflare host the MX records for my custom domain (which are required for email routing to work) and yet still use Exchange Online for sending outbound email from that same custom domain? Including using DKIM?

Near as I can tell, Exchange Online doesn’t like not being authoritative for the MX records, but I’m hoping I’m overlooking something.


Mind if I ask, what exactly is your use case for using both Office 365 / Exchange Online, AND the Email Routing, at the same time?

Such kind of set up that you describe is technically possible, but will requires some sort of fiddling.

See for example:

Each service, when configured to accept messages for, will likely request the MX records for the domain. Both of the above threads may provide a possible workaround for that.

The more stuff you stack on top of other stuff, the more fragile the overall setup will be, so I would normally advice against playing around with it like that.

According to your initial post, I see absolutely no reasons to stack the “Email Routing” on top of other stuff, such as e.g. Office 365 / Exchange Online.


Exchange Online doesn’t have any problems with any valid MX. You will be presented with an informative notice that your MX records do not match those provided by Microsoft, but as long as the MX configuration is valid, it will work.

I can assure you that the likelihood of having a valid reason to attempt to combine Cloudflare Email Routing with Exchange Online is nill. Nothing good can possibly come of it.


The main reason was to consolidate more of my reporting and policy administration to cloudflare. If it was simple to do, I’d go ahead and do it. It isn’t, however, so I’ll just leave it as-is.

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