[xxdesmus]

Hi, I'm the Head of Trust & Safety at Cloudflare. I'd be happy to discuss the specifics of your domain's DNS settings that lead to this if you'd like to email me -- justinATcloudflareDOTcom

This general issue though is addressed here: https://support.cloudflare.com/hc/en-us/articles/200168876-E...

Specifically: "Having an MX record for a root domain proxied through Cloudflare will reveal your origin web server’s IP address to potential attackers. See Why do I have a dc-######### subdomain? for further details."

This support document links to the following other support article on this topic: https://support.cloudflare.com/hc/en-us/articles/36002029651...

This article includes the following quote: "If your mail server resides on the same IP as your web server, your MX record will expose your origin IP address."